In this program, we will validate the date whether it is in correct format or not.

Consider the program:

#include <iostream>
using namespace std;

short isValidDate( short dd, short mm, short yy )
{
	if( yy < 0 )
		return 1;
		
	if( mm < 0 || mm > 12)
		return 1;
	
	if( mm == 2)
	{	
		if ( yy % 4 == 0 )
		{
				if( dd > 29 || dd < 0) 
					return 1;
		}
		else
		{
				if( dd > 28 || dd < 0) 
					return 1;
		}
	}
	else if( mm == 1 || mm == 3 || mm  == 5 || mm == 7 || mm == 8 || mm == 10 || mm == 12 )
	{
		if( dd > 31 || dd < 0) 
			return 1;
	}
	else
	{
		if( dd > 30 || dd < 0) 
			return 1;
	}
	
	return 0;
}


int main()
{
	int ret = 0;

	
	ret = isValidDate( 10, 10, 17 );
	if(ret==0)
		cout<<"Given date is valid"<<endl;
	else
		cout<<"Given date is not valid"<<endl;
	
	ret = isValidDate( 10, 15, 17 );
	if(ret==0)
		cout<<"Given date is valid"<<endl;
	else
		cout<<"Given date is not valid"<<endl;
	
	return 0;
}

Output

Given date is valid
Given date is not valid

This program can be used for date validation - to validate number of days in a month, number of months in a year.