The ternary operator

Learn to write a conditional expression in one line with ? :.

The ternary operator

With ? and : you write a conditional expression in one line. Syntax: condition ? true_value : false_value. The result is a value; you can use it in an assignment.

int a = 5, b = 9;
int max = (a > b) ? a : b;
printf("Max: %d\n", max);  // 9

Parentheses around the condition aren't required but improve readability. With if/else: if (a > b) max = a; else max = b;. Ternary is preferred for short expressions.

Ternary inside printf

You can use ternary directly inside printf; this concisely replaces an if/else block.

int n = 7;
printf("%s\n", (n % 2 == 0) ? "Even" : "Odd");

Here %s prints the string returned by the ternary. Nested ternary is possible but hurts readability; in that case prefer if/else.

Exercise Find the larger with ternary

Write a C program. Declare int a = 5; and int b = 9;. Find the larger with int max = (a > b) ? a : b;. Print with printf("Max: %d\n", max);. Put #include <stdio.h> at the top.

Show example solution

#include <stdio.h>

int main(void) {
    int a = 5;
    int b = 9;
    int max = (a > b) ? a : b;
    printf("Max: %d\n", max);
    return 0;
}

Test yourself

What does (a > b) ? a : b return?
```
int a = 5, b = 9;
int max = (a > b) ? a : b;
```
- Always a
- Always b
- Their sum
- The larger one
Show answer

The larger one — If true returns a, if false returns b; so the larger one.

Complete the ternary

int sign = (x >= 0) ? 1 : ____;

Show answer

int sign = (x >= 0) ? 1 : -1;

Match ternary and if/else

condition ?

Condition check
: true

First value
: false

Second value
if/else

Blocks

Next lesson: Nested conditionals

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