C/C++ Ternary Operator

The ternary operator (?:) in C/C++ is a shorthand for an if-else statement. It is the only operator in C/C++ that takes three operands, which is why it is called "ternary".

Syntax

(expression-1) ? expression-2 : expression-3

This operator returns one of two values depending on the result of an expression. If expression-1 evaluates to Boolean true, then expression-2 is evaluated and its value is returned as the final result. Otherwise, expression-3 is evaluated and its value is returned.

Example − Finding Maximum of Two Numbers

Let us write a program to find the maximum of two numbers using the ternary operator −

#include <iostream>
using namespace std;

int main() {
   int a = 10;
   int b = 20;
   int max = a > b ? a : b;
   cout << "Maximum value = " << max << "\n";
   return 0;
}

The output of the above code is −

Maximum value = 20

If we compare the syntax with the above example −

• expression-1 is (a > b)

• expression-2 is a

• expression-3 is b

First, the expression a > b is evaluated, which results in false since 10 is not greater than 20. Hence the value of b (20) is returned and assigned to max.

Example − Checking Even or Odd

The ternary operator can also return strings or other expressions −

#include <iostream>
using namespace std;

int main() {
   int num = 15;
   string result = (num % 2 == 0) ? "Even" : "Odd";
   cout << num << " is " << result << endl;
   return 0;
}

The output of the above code is −

15 is Odd

Example − Nested Ternary Operator

Ternary operators can be nested to handle multiple conditions, similar to if-else if-else chains −

#include <iostream>
using namespace std;

int main() {
   int a = 30, b = 30;
   string result = (a > b) ? "a is greater"
                 : (a < b) ? "b is greater"
                 : "both are equal";
   cout << result << endl;
   return 0;
}

The output of the above code is −

both are equal

Note − While nesting is possible, deeply nested ternary operators reduce readability. Use if-else statements for more than two conditions.

Ternary Operator vs if-else

Conclusion

The ternary operator (?:) is a concise alternative to if-else for simple conditional assignments. It evaluates a condition and returns one of two values based on whether the condition is true or false. While it improves brevity for straightforward cases, use regular if-else for complex or nested conditions to maintain readability.