The Conditional (Ternary) Operator

C++ Conditional Operator (Ternary)

The ternary operator is the compact way to pick one of two values. It is a little if/else squeezed into one line.

The shape

condition ? valueIfTrue : valueIfFalse

• First, decide on the condition.
• If it is true, the result is valueIfTrue.
• If it is false, the result is valueIfFalse.

Example

int time = 20;
string msg = (time < 18) ? "Good day." : "Good evening.";
cout << msg << endl;  // Good evening.

Since 20 < 18 is false, the part after the : wins.

Choosing between two values

int a = 7;
int b = 3;
int bigger = (a > b) ? a : b;  // 7

The ternary works great for one simple choice.

When not to use it

For longer or nested logic, a normal if/else is much easier to read. The ternary shines on short, single-value decisions only.

TL;DR

• result = condition ? valueA : valueB.
• If the condition is true take valueA, otherwise take valueB.
• Reading gets difficult for big bodies; use it for small decisions.