void prout(char* s)
{
    *(s+1) = 'X';
}

void main() {
    char *s1 = (char *) malloc(25);
    sprintf(s1, "Hello, World");

    char s2[] = "Hello, World";
    char* s3 = "Hello, World";


    prout(str);
    prout(s);
    prout(s3);
}