CODEWITHSUNDEEP
c++if-statementconditional-operatorleap-year
Pooja Choudhary
Pooja Choudhary

Reputation: 19

The program is giving wrong output for leap year the value at the load variable is wrong i think Ex.1900,1700

*The program is giving wrong output for century year which are not leap Ex.1900,1700.The program is giving wrong output for leap year the value at the load variable is wrong i think Ex.1900,1700. *

#include <iostream>

using namespace std;

int main()
{
    int year;
    bool t1=true;
    cout<<t1;
    bool t2=false;
    cin>>year;
    if(year%4==0)
    {
       int value=year%100?year%400?t1:t2:t1;
       cout<<value;
       if(value==t1)
       {
           cout<<"leap year";
       }
       else
       {
           cout<<"not a leap year";
       }
    }
    else
    {
        cout<<"not a leap year";
    }
}

Upvotes: 0

Views: 77

Answers (3)

JHBonarius
JHBonarius

Reputation: 11281

Once C++20 has been properly implemented by compilers (which is not yet in release) you don't have to reinvent the wheel and can use std::chrono::year::is_leap

#include <iostream>
#include <chrono>

int main() {
    using namespace std::chrono;

    year y = 1900y;
    std::cout << "year: " << static_cast<int>(y)
              << " is " << (y.is_leap()?"":"not ") << "a leap year\n";
}

godbolt

Upvotes: 1

Alan Birtles
Alan Birtles

Reputation: 36488

In addition to the fix in MikeCAT's answer you can also significantly simplify your code to just a few lines:

#include <iostream>

int main()
{
    int year;
    std::cin>>year;
    bool leap = (year % 4 == 0) && ( (year % 100 != 0) || (year % 400 == 0) );
    if(leap)
    {
        std::cout<<"leap year";
    }
    else
    {
        std::cout<<"not a leap year";
    }
}

You can use 0 being equivalent to false to make it shorter but I think the first version is more readable:

    bool leap = !(year % 4) && ( (year % 100) || !(year%400) );

Upvotes: 1

MikeCAT
MikeCAT

Reputation: 75062

year%100 becomes false when year is divisible by 100 (the remainder is zero) and becomes true when year is not divisible by 100 (the remainder is not zero).

year%400 becomes false when year is divisible by 400 (the remainder is zero) and becomes true when year is not divisible by 400 (the remainder is not zero).

Therefore, you have to judge the number as not leap year when year%100 is false and year%400 is true, and as not leap year otherwise.

In conclusion, the line

int value=year%100?year%400?t1:t2:t1;

should be

bool value=year%100?t1:year%400?t2:t1;

Also I don't think using int here to assign bool variables is reasonable.

Upvotes: 2

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