The Ternary Operator

This lesson covers C's ternary operator, so you can express a conditional in a single, concise line. It's for anyone searching "C ternary operator usage."

condition ? value-if-true : value-if-false expresses a simple if statement in one line. It's well-suited to a short branch, like "decide the message on the spot based on whether someone is an adult or a minor."

The example passes age >= 20 ? "Adult" : "Minor" directly to printf() in one line, based on age. Expressing in a single line what an if statement would take several lines to do is the biggest benefit.

A common early mistake is overusing the ternary operator until it becomes hard to read. Cramming in complex conditions makes it harder to read instead — the trick is reaching for it only for a simple, two-way choice.

In real projects, a nested ternary operator especially tends to become unreadable, so knowing when to fall back to an if statement for complex conditions matters too.

📖 Reference code

#include <stdio.h>

int main(void) {
    int age = 20;
    printf("%s\n", age >= 20 ? "Adult" : "Minor");
    return 0;
}

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🧪 This site can't compile or run C directly, so it checks on the spot whether what you typed matches the reference code (scoring happens entirely in your browser — nothing is sent anywhere).