struct_memory.c

#include <stdio.h>

#pragma pack(1)
struct my_struct
{
    unsigned char b0;
    unsigned char b1;
    unsigned char b2;
    unsigned char b3;
    unsigned char b4;
};

int main(void)
{
    struct my_struct *ptr;
    unsigned char     buffer[5];

    ptr = (struct my_struct *) buffer;

    ptr->b0 = 'h';
    ptr->b1 = 'e';
    ptr->b2 = 'l';
    ptr->b3 = 'l';
    ptr->b4 = 'o';

    for (int i = 0; i < 5; i++)
    {
        putchar(buffer[i]); // Print "hello"
    }

    return 0;
}