#include <stdio.h> // for output
#include <string.h> // string functions
#include <stdlib.h> // standard library

// In C, strings are stored as character codes ( ASCII or Unicode )
// and have a 0 at the end

int main () // execution starts here
{
    char * str = "ABCDEFG";             // string in memory. Has 0 at end
    const int BUFSIZE=256;              // size of buffer = 256 bytes
    char * buffer = malloc(BUFSIZE);    // get memory block of this size
    for (int i=strlen(str); i>0; i--)   // for loop. i decrease from string length to 0
    {
        memset(buffer, 0,BUFSIZE);      // fill buffer with zero
        strncpy(buffer,str, i);         // copy i bytes from str to buffer
        printf("%s\n", buffer);         // print buffer
    }
    return 0;
}