Ternary

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

Ternary

The ternary is a short way to write a conditional expression on one line: condition ? valueA : valueB. If the condition is true valueA is produced; if false valueB. The result can be assigned to a variable or printed directly.

For example var label = n >= 0 ? "positive" : "negative"; picks a label based on the sign of n. The ternary is the short form of if/else for simple two-way choices; avoid very complex ternaries for readability.

Ternary and if/else

The ternary is an expression; it produces a value and can be assigned to a variable. if/else is a statement; it runs a block but produces no value. They serve different needs.

For simple two-way assignments the ternary is shorter: var s = x > 0 ? "pos" : "neg";. But for complex branching with side effects (print, assignment) if/else is more readable. Practical tip: use the ternary only to pick a value; leave side effects to if/else.

Exercise Even/odd label

Declare an int variable n with the value 8. Declare a variable label and assign the ternary n % 2 == 0 ? "even" : "odd" to it. Then print label with print(label);. The output on a single line must be even.

Show example solution

int n = 8;
var label = n % 2 == 0 ? "even" : "odd";
print(label);

Test yourself

Complete the ternary

int n = 7;
var label = n % 2 == 0 ____ "even" : "odd";
print(label);

Show answer

int n = 7;
var label = n % 2 == 0 ? "even" : "odd";
print(label);

Match each part to its job

cond ?

Condition and true arm
: valueB

False arm
if/else

Two-way statement
ternary

Two-way expression
What is the output of this code?
```
int n = 7;
print(n % 2 == 0 ? "even" : "odd");
```
- true
- even
- odd
- 0
Show answer

odd — 7 % 2 == 0 is false, so 'odd' is produced.

Next lesson: Summary - Conditionals

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