add2stdio.c

#include "apue.h"

int
main(void)
{
	int		int1, int2;
	char	line[MAXLINE];

	while (fgets(line, MAXLINE, stdin) != NULL) {
		if (sscanf(line, "%d%d", &int1, &int2) == 2) {
			if (printf("%d\n", int1 + int2) == EOF)
				err_sys("printf error");
		} else {
			if (printf("invalid args\n") == EOF)
				err_sys("printf error");
		}
	}
	exit(0);
}