#include <stdio.h>

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

int main()
{
    printf("hello, world\n");
    return 0;
}

Fix gcc warning when -Wall (implicit return).
Fix gcc warning when -Wall (implicit return).

warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^