C++ Conditional Expression Operator

Introduction

A simple if statement can also be written as a conditional expression.

The following is a simple if-statement: 

#include <iostream> 

int main() /*from w  ww  .ja v a2  s.  c  om*/
{ 
    bool mycondition = true; 
    int x = 0; 

    if (mycondition) 
    { 
        x = 1; 
    } 
    else 
    { 
        x = 0; 
    } 
    std::cout << "The value of x is: " << x << '\n'; 
}

To rewrite the previous example using a conditional expression, we write: 

#include <iostream> 

int main() /* w  w w  .  j a v a2 s  . c o m*/
{ 
    bool mycondition = true; 
    int x = 0; 
    x = (mycondition) ? 1 : 0; 
    std::cout << "The value of x is: " << x << '\n'; 
}

The conditional expression is of the following syntax: 

(condition) ? expression_1 : expression_2

The conditional expression uses the unary ? operator, which checks the value of the condition.

If the condition is true, it returns expression_1.

If the condition is false, it returns expression_2.

It can be thought of as a way of replacing a simple if-else-statement with an one liner.




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