hello world用标准C语言怎么写？

Question

如题

Answer 1

#include <stdio.h>
int main()
{
printf("Hello,World!\n");
return 0;
}

Answer 2

#include <cstdio>
int main()
{
printf("Hello World!");
return 0;
}

turc好像不能运行？

Answer 3

void main(){
printf("hello world");
}

Answer 4

#include "stdio.h"
main()
{
printf("hello world");
printf("\n");
}