#include <stdio.h>
#include <stdlib.h>
#include <string.h>
char *copy_string(char *p)
{
    char *copy = (char*)malloc(sizeof(char) * (strlen(p)+1));
    if(copy = NULL)
        exit(1);
    strcpy(copy,p);
    return copy;
}

int main()
{
    char string[] = "Hello World!";
    char *new_string = copy_string(string);
    puts(new_string);
    free(new_string);
    return 0;
}