Hope this helps.. Then the size of the char array is find by dividing the size of the complete array by the size of the first variable. I will make a better assumption saying. How to get the width/height of jpeg file without using library? QGIS expression not working in categorized symbology. What if a null character is present in the middle of a string? of that type,And, of ((I'm keeping my comment so that others dont ask the same question, or don't apply the same technique directly in C++, as C++'s type-system is a bit more complex)). Learn more, Find size of array in C/C++ without using sizeof, How to use sizeof() operator to find the size of a data type or a variable in C#, How to swap two numbers without using a temp variable in C#, Swapping two variable value without using third variable in C/C++. It uses a pointer which is not valid according to the question. In C programming language you can check the size of a variable using sizeof operator. 8-bit bytes are by far the most common, but there could be (and have been!) But it is my recommendation to use the sizeof() operator to calculate the size of the structure in a program whenever you need to calculate the size of the structure. One simple way of doing this would be using arrays. The question asks how to do this "without declaring a variable or pointer of that type.", There are multiple issues with that answer. Save my name, email, and website in this browser for the next time I comment. - Aticleworld. (adsbygoogle = window.adsbygoogle || []).push({}); When doing pointer math I like to cast the pointers to intptr_t or uintptr_t not char*. How to find the address of a string in memory using GDB? I would write the following code to find the size of an integer in bytes (assuming no sizeof command and byte = 8 bits): Code: int i = 1; int count = 1; while (i <<= 8) { count++; } //count should contain the size of the integer i in bytes. int x; x = sizeof (int); To get the size of a variable, without using the sizeof, try the following code . This trick is highly Does illicit payments qualify as transaction costs? You could puzzle it out by reading the ABI for your particular processor, which explains how structures are laid out in memory. It's potentially No, we can even find the size of entire expressions using the operator. C/C++ add input to stdin from the program? But here I am interested in calculating the size of structure in C without using the sizeof() operator. How will you find the size of a structure in C/C++ language without using sizeof operator. Does http_proxy automatically work in Linux for all applications? Is energy "equal" to the curvature of spacetime? However, I don't really see a valid reason not to use sizeof, but I'm sure you must have one. It is C++ while there is only a C language tag and it also invokes undefined behaviour when printing a pointer with. Max Distance between two occurrences of the same element. Save my name, email, and website in this browser for the next time I comment. This trick is highly dependent on the layout your compiler uses for stack variables though! Counterexamples to differentiation under integral sign, revisited. You could puzzle it out by reading the ABI for your particular processor, which explains how structures are laid out in memory. You will get : and from this, the expected size of anything. Declare 2 pointer variable of the same type and assign the address of the variable to them and then increment one of them. Please enter your email address. Why do some airports shuffle connecting passengers through security again. By omitting the parens you tell the reader that this is an object, not a type. Why is not sizeof for a struct equal to the sum of sizeof of each member in C/C++? But I was just wondering if there's any way by which we can calculate the size of the pointer without the sizeof operator. why cant we just subtarct like piData2 piData1, You should read this article, https://aticleworld.com/pointer-arithmetic/, Your email address will not be published. Are defenders behind an arrow slit attackable? sizeof() is an operator in c programming language, which is used to get the occupied size by the variable or value. To my mind, this fits into the category of "how do I add two ints without using ++, += or + ?". It's a waste of time. You can try and avoid the mon Making statements based on opinion; back them up with references or personal experience. Output. Why of course? How to portably print a int64_t type in C. Add a new light switch in line with another switch? Then we divide that number with the sizeof of the data type; in this program, it is int. To use the sizeof(), we can take the value using a variable x, using &x, it will print the address of it. Key point is when a pointer is incremented, it actually moves by the size equal to the object it is pointing, so here the size of the class (of which the object it is pointing to). The usage of sizeof is simple. Switch statement with huge number of cases, Delete the last integer in an array without it becoming zero, Use poll() to check for file modification, How to extract a negative number from a string, How would you define a simple "min" method in obj-c. Using the sizeof() operator we can calculate the size of the structure straightforward to pass it as a parameter. It contains well written, well thought and well explained computer science and programming articles, quizzes and practice/competitive programming/company interview Questions. Now can I find the size of the variable 'i' without sizeof operator? The idea is to use pointer arithmetic ( (& (var)+1)) to determine the offset of the variable, and then subtract the original address of the variable, yielding its size. Unfortunately things like padding, compiler settings, etc.. would all play a part too. How does this piece of code determine array size without using sizeof( )? How to link using GCC without -l nor hardcoding path for a library that does not follow the libNAME.so naming convention? For example: We are using sizeof operator to calculate the sizeof fields.. . confusion between a half wave and a centre tapped full wave rectifier. Output. The size of a variable depends on its type, and C++ has a very convenient operator called sizeof that tells you the size in bytes of a variable or a type. How can I do that? This is because of the extra padding byte which inserts by the compiler to avoid alignment issues. Note that char may have more than 8 bits, however Can it really be more than 8 bits in C? I am a professional blogger, present started writing artilces on job description template, Your email address will not be published. Available since C89 solution that in user code: Easy enough to do using standard code as hinted by @steve jessop, which expands to an integer constant expression that has type size_t, the value of which is the offset in bytes, to the structure member , from the beginning of its structure C11 7.19 3. By creating foo[2], I will now have 2 consecutive foo objects in memory. In C language, sizeof() operator is used to calculate the size of structure, variables, pointers or data types, data types could be pre-defined or user-defined. Can we keep alcoholic beverages indefinitely? The correct answer to this interview question is "Why would I want to do that, when sizeof() does that for me, and is the only portable method of doing so?". When adding multiple answers to a question, please include an explanation to them which explains the difference. Padding is possible. The trick is to make a pointer object, save its address, increment the pointer and then subtract the new address from the previous one. Also sizeof is an operator and does not require parentheses unless operating on a type. ( {x __tmp_x_ [2]; \. No. Lastly, %d, is for printing ints, use the macros in inttypes.h to print objects like intptr_t or %zu to print the result of the sizeof operator. In the previous article all about the pointer, we have read that using the pointer subtraction we can calculatethe number of bytes between the two pointers. How does the compiler allocate memory without knowing the size at compile time? You can use the following macro, taken from here: The idea is to use pointer arithmetic ((&(var)+1)) to determine the offset of the variable, and then subtract the original address of the variable, yielding its size. I think that parentheses is good for the readability and there is no side effect for parentheses. Calculating the size of structure in bytes without using sizeof. Why does it matter if this person should use something or not? I have tried this method, but i am getting a warning .. Guest Article Look, sizeof is the language facility for this. Well, I am an amateur..but I tried out this problem and I got the right answer without using sizeof. @Charles Balley this question is asked in Cisco interviews. Connect and share knowledge within a single location that is structured and easy to search. In C language, sizeof() operator is used to calculate the size of. Why is Singapore currently considered to be a dictatorial regime and a multi-party democracy by different publications? How to check if widget is visible using FlutterDriver. How can I move to a pointer position directly without using the ++ operator? Not the answer you're looking for? Let us see an example for better understanding: In the above declaration, Integer is the largest structure member (4 bytes) so to prevent the performance penalty compiler inserts some extra padding bytes to improve the performance of the CPU. Heres simple program to find size of variables using sizeof() operator in C Programming Language. Improve INSERT-per-second performance of SQLite. Using the sizeof () systems with 9-bit and even 36-bit bytes, and a system with 32-bit bytes is conceivable, if it doesn't already exist. - AticleWorld, What is importance of struct hack in c? Create a pointer to structure and assign the address of the array. @KeithThompson: Oops yes! How can you find the size of a datatype without creating a variable or pointer, or using sizeof of the datatype? Why was USB 1.0 incredibly slow even for its time? So the size of the InfoData will be 12 bytes due to the padding bytes. When should i use streams vs just accessing the cloud firestore once in flutter? Calculating the size of structure in c without using the sizeof() operator seems to be difficult but with the help of pointers, we can do it easily. Your email address will not be published. Do shared libraries use the same heap as the application? We can also calculate the size of the structure using the pointer subtraction. Greedy Solution to Activity Selection Problem. Here we need to use some techniques to calculate the size of the structure in C. I am describing this technique, using a few examples. A recursive method to find depth of a any(not necessarily complete) Binary tree, Swap number digit order by separate a number into arrays and then merge, C : Passing bi-dimensional array of pointers as argument, Why does quicksort take longer when sorted in descending order vs ascending order, Do the names of the args passed to main() matter, Should you free at the end of a C program. WebAlthough the standard says "The sizeof operator shall not be applied to an expression that has function type" (6.5.3.4/1), in GNU C, the result of doing this is well defined: "sizeof is also allowed on void and on function types, and returns 1" ~ GCC, 6.23 Arithmetic on void- and Function-Pointers Also have a look at: Why is the size of a function in C always 1 byte? document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); About How do I arrange multiple quotations (each with multiple lines) vertically (with a line through the center) so that they're side-by-side? Note: Structure padding also affects the size of the structure in C. When we increment the pointer then pointer increases a block of memory (block of memory depends on pointer data type). Heres simple program to find size of variables using sizeof () You are given have a datatype, say X in C. The requirement is to get the size of the datatype, without declaring a variable or a pointer variable. By using this website, you agree with our Cookies Policy. In order to use sizeof the zoperator, you can pass variable to the operator. Here firstly, we calculate the size of the whole array or calculate the memory it is taking up. library to work with historical (big) dates and time (eg, 11,043 BC)? If you found any error or any queries related to the above program or any questions or reviews , you wanna to ask from us ,you may Contact Us through our contact Page or you can also comment below in the comment section.We will try our best to reach up to you in short interval. Well, I am an amateur..but I tried out this problem and I got the right answer without using sizeof. Hope this helps.. ( (unsigned int) (&__tmp_x_ [1]) - (unsigned int) (&__tmp_x_ [0])); \. }) How is sizeof implemented in C? How to swap two arrays without using temporary variable in C language? How to find the position of the only-set-bit in a 64-bit value using bit manipulation efficiently? Perl regex to find the name of a packed struct without using variable length lookbehind? Console program does not execute correctly when run from SciTE, C. Segmentation Fault when function modifies dynamically allocated 2d array. How to change background color of Stepper widget to transparent color? Code Explanation. thank you for giving example of size of operator for last one week i am looking for this information Site design / logo 2022 Stack Exchange Inc; user contributions licensed under CC BY-SA. The word "byte" does not always mean "8 bits". This takes into account that a C++ byte is not always 8 binary bits, and that only unsigned types have well defined overflow behaviour. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Note that I don't declare a variable of type or pointer to X. You can try and avoid the monsters of undefined behaviour by doing something like this. But here I am interested in calculating the size of structure in C without using the sizeof() operator. How to access pointer inside a structure in c. How to use the structure of function pointer in c language? The second most important use case for this operator is allocating a dynamic memory, so we use the sizeof operator when allotting the space. printf("%u\n", (int)(&a+1)-(int)(&a)); People also ask. Ready to optimize your JavaScript with Rust? How to copy local variable to global variable if both have the same names in C without using a third variable? invalid application of 'sizeof' to incomplete type 'struct array[]', How to find the size of a variable without using sizeof. Below is the source code for C program to find size of variables using sizeof() operator which is successfully compiled and run on Windows System to produce desired output as shown below : Aboveis the source code for C program to find size of variables using sizeof () operator which is successfully compiled and run on Windows System.The Output of the program is shown above . By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. It is not a wastage of time and neither is it a stupid question. What properties should my fictional HEAT rounds have to punch through heavy armor and ERA? How to share internet from mobile to PC without hotspot? . just comment what program do u want , we provide u better support .Thanks. By this code script the size of any data can be calculated without sizeof operator.Just change the float in line 1 with the type whose size you want to calculate. Asking for help, clarification, or responding to other answers. Lost your password? (If a field is stored in two words of memory then it will take 2 reads, but if we leave the space in between so that the field is stored in just one word, the read & write operation will take only one cycle, read more about it here). I believe this interview question is intended to ask you to think outside the box. Look, sizeof is the language facility for this. The only one, so it is the only portable way to achieve this. For some special cases you could g To understand this example, you Affordable solution to train a team and make them project ready. Hence the resulting address of (&x+1) will be 2 bytes more than the base address of the variable x. The compiler is always free to add additional padding anywhere, so there is no 'expected size' - except for sizeof(char), which is defined to be 1. See, Method-1 in solution). Below statement will give generic solution: i is a variable name, which can be any data type (char, short, int, float, double, struct). We can find the size of an array Look into the compiler sources. This padding is an extra memory which will not be used to store anything, but to optimize the read/write of individual fields of a structure variable. Look into the compiler sources. You will get : the size of standard data types. the rules for padding of structs and from this, the expected size o About us Articles Contact Us Online Courses, 310, Neelkanth Plaza, Alpha-1 (Commercial), Greater Noida U.P (INDIA). I am trying to find the size of an integer. Explanation: By using the &x, we get the base address of the variable x and by adding 1 to it we get the base address of next short int type. How do I determine the size of an object in Python? In C++ it is defined as exactly 1 byte (logic inference: sizeof() returns the size of the argument in bytes, sizeof(char)==1 => char is exactly one byte). To understand this better, let us look at a few examples. NOTE: Simply consider that 'i' is declared and dont bother if it is an int or char or float or double datatype. sizeof (int) [required] sizeof foo_variable [not required]. It is also an important interview question that is generally asked by the interviewer to check the understanding of pointer. The possibility of padding prevent all hopes without the knowledge of the rules used for introducing it. Using the sizeof() operator we can calculate the size of the structure straightforward to pass it as a parameter. WebIn C language, sizeof () operator is used to calculate the size of structure, variables, pointers or data types, data types could be pre-defined or user-defined. We make use of First and third party cookies to improve our user experience. Example: sizeof (var1); sizeof is not a function. I am an embedded c software engineer and a corporate trainer, currently, I am working as senior software engineer in a largest Software consulting company . A Computer Science portal for geeks. rev2022.12.11.43106. How to change the stack size using ulimit or per process on Mac OS X for a C or Ruby program? What is the size of operator? Which is better USB tethering or Mobile hotspot? All rights reserved. WebHere is how to find size of a structure without sizeof operator. This is the code: Being a riddle, you have to find an unusual, and possibly absurd, method to do it. How to find the size of structure in C without using sizeof? In C language, sizeof () operator is used to calculate the size of structure, variables, pointers or data types, data types could be pre-defined or user-defined. Using the sizeof () operator we can calculate the size of the structure straightforward to pass it as a parameter. I thought of using standard header files which contain size and range of data types but that doesn't work with user defined data type. Surely, you could also just #include or . WebHere's a trick for finding the size of a variable without using sizeof--not something you'd generally do, but it demonstrates the ability to use pointer arithmetic. How is the size of a variable length array computed at runtime in C99? You can use the following macro, taken from here: The idea is to use pointer arithmetic ((&(var)+1)) to determine the offset of the variable, and then subtract the original address of the variable, yielding its size. why do we need to cast the variable to char * For some special cases you could generate un-portable code that used some other heuristic to understand the size of particular objects[*] (probably by making them keep track of their own size), but you'd have to do all the bookkeeping yourself. Write a C program to find size of variables using sizeof () operator. disclaimer. A lot of these answers are assuming you know what your structure will look like. clone system call's argument stores in stack or somewhere else? Why do quantum objects slow down when volume increases? It's basically defined as the smallest individually addressable unit of memory. Csharp Programming Server Side Programming. To get the size of a variable, sizeof is used. int x; x = sizeof (int); To get the size of a variable, without using the sizeof, try the following code . // without using sizeof byte [] dataBytes = BitConverter.GetBytes (x); int d = dataBytes.Length; Here is the complete code. hi this is Gloria Cartwright, Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. Right method is to allocate an array of structure and compare the memory addresses of consecutive elements of an Array: Note that if we dont convert the address to char* then the answer will always be 1 (because it will talk about the memory block & not memory location). In this example, you will learn to evaluate the size of each variable using sizeof operator. When can I find out more? But unless you're writing a compiler it's surprising you don't want to just use sizeof, which is the One Right Way to solve this problem. if X is datatype: #define SIZEOF(X) (unsigned int)( (X *)0+1 ) https://aticleworld.com/pointer-arithmetic/, What is flexible array member in C? Is there a higher analog of "category with all same side inverses is a groupoid"? How to find the size of the L1 cache line size with IO timing measurements? // without using Swapping two variables without using third variable, Find minimum cost to travel to the destination, Find kth largest element in running stream of numbers. How do I determine the size of my array in C? [*] Objects in a very general sense rather than the OOP sense. WebFind size of variables using sizeof () operator. I am trying to find the size WebThen, the size of the char variable is calculated using sizeof() operator. WebC++ Program to Find Size of int, float, double and char in Your System. For example, if you have an int16_t i variable located at 0x0002, you would be subtracting 0x0002 from 0x0006, thereby obtaining 0x4 or 4 bytes. Note: This code uses "%zu" which requires C99 onward. We do not currently allow content pasted from ChatGPT on Stack Overflow; read our policy here. To get the size of a variable, without using the sizeof, try the following code , Enjoy unlimited access on 5500+ Hand Picked Quality Video Courses. How to find the size of a variable without using sizeof. More tips. Would love your thoughts, please comment. To find the size of variable, sizeof operator is Here is the generic approach to find size of any variable without using sizeof operator: Suppose we want to find the size of variable 'Var' of data type D(for example an integer variable 'Var'). WebHere we are going to do a pointer arithmetic trick to get the size of a variable. For example, if you have an int16_t i variable located at 0x0002, you would be subtracting 0x0002 from 0x0006, thereby obtaining 0x4 or 4 bytes. How can you find the size of a datatype without creating a variable or pointer, or using sizeof of the datatype? To get the size of a variable, sizeof is used. In C++, we use sizeof() operator to find the size of desired data type, variables, and constants. The sizeof of a structure is not always equal to the sum of sizeof of each individual member. Thanks for contributing an answer to Stack Overflow! Required fields are marked *. How to find the physical address of a variable from user-space in Linux? Now, we know for the fact that in arrays elements of the same datatype are stored in a contiguous block of memory. Copyright 2016-2020 CodezClub.com All Rights Reserved. For example: struct Student{ int rollno; char name[25]; To get the size of a variable, sizeof is used. There may be padding in between the members. According to the C standards, alignment of structure totally depends on the implementation. While 0 is guaranteed to mean "null pointer" in all implementations, it doesn't have to be represented internally by address 0, in which case this will fail. You can directly pass a type like: sizeof (int); . #include struct By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Data Structure Alignment : Linker or Compiler. I know that sizeof is an operator, I have mentioned in the beginning of the article. Interview Questions On bitwise Operators C, Interview Questions On Memory Allocation C, Machine Learning, Data Science and Deep Learning, Statistics for Data Science, Data and Business Analysis. Why isn't sizeof for a struct equal to the sum of sizeof of each member in C/C++? Using the sizeof( ) Operator. I have a data type, say X, and I want to know its size without declaring a variable or pointer of that type and of course without using sizeof operator. Try this: int a; WebThe sizeof() datatype returns the size of a data type. In this article, I will describe some methods to calculate the size of the structure in c without using the sizeof the operator. I was looking for the answer but didn't find any solutions I liked here. There may be padding along the fields of a structure. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); document.getElementById( "ak_js_2" ).setAttribute( "value", ( new Date() ).getTime() ); This post is priceless. In C language, sizeof() operator is used to calculate the size of structure, variables, pointers or data types, data types could be pre-defined or user-defined. Using the sizeof() operator we can calculate the size of the structure straightforward to pass it as a parameter. The sizeof( ) operator can be used to find the size of data types and expressions. However, I don't really see a valid reason not to use sizeof, but I'm sure you must have one. @Paul: I understand that you are insisting on being safe and being dependent on compiler. Copyright 2022 www.appsloveworld.com. sizeof(int); For double datatype - AticleWorld, 8 Tips to Increase the Performance of Your "C" Code. Stay tuned! Why would Henry want to close the breach? After creating the structure, create an array of structures, Here RamInfo[2]. Login to Answer. It's been ages since I wrote any C code and I was never good at it, but this looks about right: I'm sure someone can tell me plenty of reasons why this is wrong, but it prints a reasonable value for me. Your email address will not be published. How to create an array without declaring the size in C? What might be the point in putting a variable exactly in the "STACK" section with __attribute__ ((section("STACK"))? C. Aricent. Find size of variables using sizeof() operator, Welcome to Coding World | C C++ Java DS Programs, C Program to display sum of even and product of odd numbers, Write a C Program to find the gross salary and net salary, Write a C Program to find the roots of quadratic equation, Write a C program to find HCF of two numbers, Learn Java: An Easy And In-Demand Programming Language. How does sizeof know the size of the operand array? How to find sizeof array in C/C++ without using sizeof? Required fields are marked *. How to find size of a variable without using sizeof operator Author: Amit Khandelwal 1. To learn more, see our tips on writing great answers. And those are implementation dependent. WebWhat does variable in size mean? Implement your own sizeof operator using C++. Blog Posts How can I swap two strings without using a third variable in Java? If you could at least allocate space for the variable, and fill some sentinel value into it, you could change it bit by bit, and see if the value changes, but this still would not tell you any information about padding. How to find the size of an int[] in C/C++? It's been ages since I wrote any C code and I was never good at it, but this looks about right: I'm sure someone can tell me plenty of reasons why this is wrong, but it prints a reasonable value for me. In general, using the sizeof operator is a much better idea. WebC Program to Find the Size of int, float, double and char. Since I want a generic solution I am simply mentioning that variable 'i' can be of any one of the datatypes namely int, char, float or double. how to find out the page size of a processor using C program and malloc? See my answer. The correct answer to this interview question is "Why would I want to do that, when sizeof() does that for me, and is the only portable method of d How do I programmatically return the max of two integers without using any comparison operators and without using if, else, etc? Japanese girlfriend visiting me in Canada - questions at border control? Next in this series: how to obtain the address-of without using an ampersand. I mean how about writing our own sizeof operator. Calculating the size of structure in c without using the sizeof() operator seems to be difficult but with the help of pointers, we can do it easily. So here we will use this technique to calculate the size of a structure. How to pass a constant array literal to a function that takes a pointer without using a variable C/C++? Help us identify new roles for community members, Proposing a Community-Specific Closure Reason for non-English content, How to find the size of a variable without using sizeof. How would you create a standalone widget from this widget tree? Solution 1. //don't try to do this with doubles. The possibility of padding prevent all hopes without the knowledge of the rules used for introducing it. And those are implementation dependent. Get the address of the first element using the sData[0] and sData[1]. Find centralized, trusted content and collaborate around the technologies you use most. This should give you the size of your variable, Program to find Size of the variable without using sizeof operator, I hope that below code would solve your problem in c++ without using sizeof() operator, for any variables like (int, char, float, double, char, short and many more). whenComplete() method not working as expected - Flutter Async, iOS app crashes when opening image gallery using image_picker. WebHow would you determine size of a variable without using sizeof? Subtract the pointers to get the size of the structurein c. After creating the structure, create an array of structures, Here sData[2]. Swap two Strings without using temp variable in C#. I have working experience of different microcontrollers (stm32, LPC, PIC AVR and 8051), drivers (USB and virtual com-port), POS device (VeriFone) and payment gateway (global and first data). How to get the size of a const char pointer, Getting the size of a malloc only with the returned pointer, Size of short, int, long, float, double long, double, char. create an array of structures, Here aiData[2]. Assuming did my pointer arithmetic correctly, this should be the ticket - and its portable! Find the difference between the above 2 pointers using a type cast. I would expect that to be rare for an. Interview questions on bitwise operators in C. 10 questions about dynamic memory allocation. How to swap two numbers without using the third or a temporary variable using C Programming? (Note: sum of sizes of all fields of a structure may not be equal to the exact memory allocated to the structure. What does sizeof (function(argument)) return? Why isn't sizeof for a struct equal to the sum of sizeof of each member? It is a compile-time execution operator. Lets say you need to find the size of int datatype . Agree Is MethodChannel buffering messages until the other side is "connected"? To my mind, this fits into the category of "how do I add two ints without using ++, += or + ?". WebBy this code script the size of any data can be calculated without sizeof operator.Just change the float in line 1 with the type whose size you want to calculate. It is also an important interview question that is generally asked by the interviewer to check the. It's potentially different for each processor. The question is how to do it without using sizeof and we can either be helpful in answering it or not. It's a waste of time. How can one print a size_t variable portably using the printf family? int a,int b char *p1,*p2; p1= (char*)a; p2= (char*)b; p1-p2. How can I get the size of a memory block allocated using malloc()? 34,385. affiliate-disclosure Create a pointer to structure and assign the NULL pointer. Program. How to build completely new data type of size n in C or C++ without using any of the user defined data type? @2501 Padding perhaps. if X is a variable: #define SIZEOF(X) (unsigned int)( (char *)(&X+1)-(char *)(&X) ) So you may be thinking about whether we can only find the size of variables using the sizeof( ) operator. For example, if you have How to calculate the Size of Folder using C#? How to find the size of a variable without using sizeof. The entire point of this website is to help others out, not to pick apart a question until it conforms to what we want. What do you mean "of course without using sizeof"? Subtract both addresses to get the size of the structure. 5. Create pointers to the structure and assign the address of the first and second element of the array. You can use the following macro, taken from here: #define sizeof_var( var ) Follow-up question: I want to include a header file I wrote, without using any preprocessor directives, of course. Write a C program to find size of variables using sizeof() operator. Get the base address of the variable 'Var' using address of(&) operator. WebYou may be tempted to calculate the size of all the fields of structure, then compute the sum of all these sizes and get the result. You may be tempted to calculate the size of all the fields of structure, then compute the sum of all these sizes and get the result. Variable-size data is data whose size is not known at compile time or whose size can change at run time. Then, the size of each variable is evaluated using sizeof operator. E.g. You will receive mail with link to set new password. This program declares 4 variables of type int, float, double and char. So, by exploiting this fact I came up with following: For the following user-defined datatype. How do you find the size of a variable csizeof. C++ Solved programs, problems/Examples with solutions, Write a C Program to find Mean, Variance and Standard deviation of n numbers, C++ Program to find Factorial of a number using class. Thanks mark for the suggestion. TabBar and TabView without Scaffold and with fixed Widget. Is this possible? The C-FAQ claims that there do exist such machines. Now can I find the size of the variable 'i' without sizeof operator? WebThe idea is to use pointer arithmetic ((&(var)+1)) to determine the offset of the variable, and then subtract the original address of the variable, yielding its size. #define __SIZE_OF__ (x) \. WebHere's a trick for finding the size of a variable without using sizeof--not something you'd generally do, but it demonstrates the ability to use pointer arithmetic. Is using sizeof on a variable where a type of the same name exists well defined? The only one, so it is the only portable way to achieve this. Who cares if it'll ruin an interview question? WebC program to print size of variables using sizeof() operator. 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