Hello world C89-90, C95

/* Hello world program */
/* Languages:
    - C89 (ANSI X3.159-1989)
    - C90 (ISO/IEC 9899:1990/Cor 2:1996)
    - C95 (ISO/IEC 9899:1990/AMD1:1995)
*/

#include <stdio.h>

int main(void)
{
    puts("Hello world!");
    return 0;
}