C++ Primer, Fifth Edition

4.7. The Conditional Operator

The conditional operator (the ?: operator) lets us embed simple if-else logic inside an expression. The conditional operator has the following form:

cond  ? expr1  : expr2;

where cond is an expression that is used as a condition and expr1 and expr2 are expressions of the same type (or types that can be converted to a common type). This operator executes by evaluating cond. If the condition is true, then expr1 is evaluated; otherwise, expr2 is evaluated. As one example, we can use a conditional operator to determine whether a grade is pass or fail:

string finalgrade = (grade < 60) ? "fail" : "pass";

The condition checks whether grade is less than 60. If so, the result of the expression is "fail"; otherwise the result ...