C++ Primer Plus, Fourth Edition

The ?: Operator

C++ has an operator that often can be used instead of the if else statement. This operator is called the conditional operator, written ?:, and, for you trivia buffs, it is the only C++ operator that requires three operands. The general form looks like this:

					expression1 ? expression2 : expression3
				

If expression1 is true, then the value of the whole conditional expression is the value of expression2. Otherwise, the value of the whole expression is the value of expression3. Here are two examples showing how the operator works:

5 > 3 ? 10 : 12  // 5 > 3 is true, so expression value is 10
3 == 9? 25 : 18  // 3 == 9 is false, so expression value is 18

We can paraphrase the first example this way: If 5 is greater than 3, the expression ...