#include <stdio.h>
#include <string.h>

int main(void) {
    char dest_arr[] = "DDDAAABBB";
    // to , from , size
    
    printf("length of string is %d \n", strlen(dest_arr));

    // in case of overlap behavior of memcpy is undefined.
    printf("string before memcpy is %s \n", dest_arr);
    memcpy( dest_arr + 3, dest_arr, 6);
    printf("string after memcpy is %s \n", dest_arr);

    // retintialising the string.
    strcpy(dest_arr, "DDDAAABBB");
    
    // note that memmove detects overlap of "AAA" and copy that first.
    printf("string before memmove is %s \n", dest_arr);
    memmove( dest_arr + 3, dest_arr, 6);
    printf("string after memmove is %s \n\n", dest_arr);
    
    // use of memset
    memset(dest_arr,0x31,strlen(dest_arr));
    printf("string after using memset is %s \n\n", dest_arr);
}