#include <iostream>
#include <string>
using namespace std;

string WeekDay(int day)
// precondition: 0 <= day <= 6
// postcondition: return "Sunday" for 0,
//                     	"Monday" for 1, 
//			…  	"Saturday" for 6
{
  if (0 == day) return "Sunday";
  else if (1 == day) return "Monday";
  else if (2 == day) return "Tuesday";
  else if (3 == day) return "Wednesday";
  else if (4 == day) return "Thursday";
  else if (5 == day) return "Friday";
  else if (6 == day) return "Saturday";
}

int main()
{
	string dayName;
	int dayNum;
	cout << " enter day (0-6): ";
	cin >> dayNum;
	dayName = WeekDay(dayNum);
	cout << "Corresponding day is: " << dayName << endl;

    cout << WeekDay(5) << endl;  //displays Friday

    // int j = WeekDay(0);  //this is syntax error since right-hand-side is string but left-hand-side is integer.

    cout << WeekDay(2.1) << endl;   //displays Tuesday

    string s = WeekDay(22);  // Syntax OK. However, since WeekDay does not return anything for argument 22, your program would crash or behave unexpectedly.

    WeekDay(3);  //syntactically this is OK, but it is a meaningless function call since you do not use the returned value.

    return 0;
}