#include <stdio.h>  //Library function printf
#include <unistd.h> //System call write and syscall

// 0 stdin
// 1 stdout
// 2 stderr 

int main(void){
    // man 3 printf
    printf("Hello!\n");

    // man 2 write
    write(1, "Hello!\n", 7);
    
    // man 2 syscall
    syscall(1, 1, "Hello!\n", 7);
     
    return 0;
}