C program to print memory representation of a C variables

• Write a program in C to show hexadecimal memory representation of a variable.

Required knowledge: sizeof operator

Algorithm to print memory representation of a variable

• Get the base address of the variable using address of(&) operator and size of variable in bites using sizeof() operator.
• Type cast the base address of variable to character pointer.
• Now, iterate for size of variable(one byte at a time) and print hexadecimal representation of memory location using %x format specifier of printf function.

C program to print memory representation of a variable

#include <stdio.h>

/*
  This function takes base address of a memory 
  location(variable) and  print 'size' bytes from 
  'address' in hexadecimal format
 */
void printBytes(unsigned char *address, int size) {
    int count;
    for (count = 0; count < size; count++){
        printf("%.2x ", address[count]);
    }
    printf("\n");
}

int main() {
    int i = 1;
    float f = 5.0;
    int *ptr = &i;
    /* print memory map of integer */
    printBytes((unsigned char *)&i, sizeof(int));
    /* print memory map of float */
    printBytes((unsigned char *)&f, sizeof(float));
    /* print memory map of pointer */
    printBytes((unsigned char *)&ptr, sizeof(int *));
    
    return 0;
}

Output

01 00 00 00
00 00 a0 40
4c fe 22 00 00 00 00 00