-----------------------program1.c
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

void check(char *a){
    printf("%c\n", a);
}

int main(void){
    check("hello world");
    return 0;
}
-------------------------
>  ( or "H", but not "h" )
>
( not as i expected )
-------------------------program2.c
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
int main(void){
    char arr[] = "hello_world";
    char *p = arr;
    printf("%c\n", *p);
    return 0;
}
-------------------------
> h
>
( as i expected )