Question

How to find the size of structure without using sizeof operator in C

Answer 1

#include <stdio.h> 
 
struct  test
{
    int n;
    char ch;
    float f;
};
 
int main(int argc, char **argv) 
{ 
    struct test arr[2];
    
    int size = (char*)&arr[1] - (char*)&arr[0];
    
    printf("%d",size);
    
    return(0);
}

 
 
/*
 
run:
 
12
 
*/

 

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Answer 2

#include <stdio.h> 
 
struct  test
{
    int n;
    char ch;
    float f;
};
 
int main(int argc, char **argv) 
{ 
    struct test t;
    struct test *p = &t;

    int size = (char*)(p + 1) - (char*)p;
    
    printf("%d",size);
    
    return(0);
}

 
 
/*
 
run:
 
12
 
*/

 

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