### Program to check whether a year is leap year or not

#include<iostream>
using namespace std;
int main()
{
int year;
cout << "Enter an Year=";
cin >> year;
if (year % 4 == 0 || year % 400 == 0)
cout << "This is a Leap year" << endl;
else if (year % 100 != 0)
cout << "This is Not Leap year" << endl;
return 0;
}
`if (year % 4 == 0 || year % 400 == 0)`

This looks suspicious.

If the left is true, the right will always be true; if the left is false, the right will be false.

So why does the right exist?
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"If the left is true, the right will always be true"

false
Guys, srsly ... try it with 2004 :

2004 % 4 = 0
2004 % 400 = 4

So no if the left is true the right will not always be true !!
Nuts. That'll teach me to scan code too quickly.

What was the actual question?
 ``123456789101112131415161718192021222324252627282930313233`` ``````#include int main() { std::cout << "Enter an year: "; int year = 0; std::cin >> year; // An year is leap if: // - BOTH can be evenly divide by 4 // - AND if can be evenly divided by 100, can be divided by 400 TOO if (year % 4 == 0) { if(year % 100 != 0) { // it can't be divided by 100, but it can by 4: it's leap std::cout << "This is a leap year\n"; } else if(year % 400 == 0) { std::cout << "This is a leap year\n"; } else { std::cout << "This is not a leap year\n"; } } else { std::cout << "This is not a leap year\n"; } // A more 'compressed' logic is: // An year is leap if: // - EITHER can be evenly divide by 4 AND can NOT be divided by 100 // - OR it can be divided by 400 if( (0 == year % 4 && 0 != year % 100) || (0 == year % 400) ) { std::cout << "This is a leap year\n"; } else { std::cout << "This is not a leap year\n"; } return 0; }``````

@Enoizat

Your code will output "This is a leap year" twice if the year is 400 or some other values. So this is a flawed program.
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 ``1234567891011`` ``````#include using namespace std; bool isLeap( int year ) { return !( year % 4 ) && ( year % 100 || !( year % 400 ) ); } int main() { int year; cout << "Enter year: "; cin >> year; cout << year << ( isLeap( year ) ? " is " : " is not " ) << "a leap year"; }``````