prog.13.1.c

#include <stdio.h>

#define		YES		1
#define		NO		0

// Function to determine if an integer is even

int isEven (int number)
{
	int answer;

	if ( number % 2 == 0 )
		answer = YES;
	else
		answer = NO;

	return answer;
}

int main (void)
{
	int isEven (int number);

	if ( isEven (17) == YES )
		printf ("yes  ");
	else
		printf ("no  ");

	if ( isEven (20) == YES )
		printf ("yes\n");
	else
		printf ("no\n");

	return 0;
}