Java Ternary Operator With Program Example

Java supports a special type of operator which can be used in place of a certain if-then-else statement situation. It is represented by ‘?:’ . It concise the code structure and improves the code readability.
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As name suggest, ternary, it consists of three parts :
  • condition
  • truthy statement
  • falsy statement
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Based on condition evaluation, the operator decides which statement, tuthy or falsy that will be assigned to a variable. It is the only operator that uses three operands.
Syntax:
expression1 ? statement 1 : statement 2
expression1 would always be a boolean expression, if it returns true then statement1 (followed by ?) would be executed, otherwise, statement2 would be returned. statement1 and statement2 can’t be void and always return compatible type.
Here’s an example,
String result = ( x == y ) ? “a true statement ” : “ a false statement”

When the Java compiler reaches this statement, if expression (x == y) gets evaluated as true, then “a true statement ” would be returned, if the expression is determined as false, then “a false statement” ( the statement after would be returned) .

At last, the returned statement would be assigned to the respective variable.
Typically, if-then-else situation can be replaced by a ternary operator.

if (voterAge < 18) {
System.out.println("You're not eligible for voting");
} else {
System.out.println("You can vote");
}
Using ternary operator:
System.out.println(voterAge < 18 ? "You're not eligible for voting" : "You can vote");

Java program to show the working of ternary operator

public class TernaryOperator {
public static void main(String[] args) {
Scanner inputReader = new Scanner(System.in);
System.out.print("Please enter your age : ");
int voterAge = inputReader.nextInt();
String msg = voterAge < 18 ? "You're not eligible for voting" : "You can vote";
System.out.println(msg);
}


}
Output:
Please enter your age : 23
You can vote
Please enter your age : 12
You're not eligible for voting

 

Where to use the Ternary Operator?

Ternary operator returns a value that is mandatorily required to assign to a variable or used. In contrast, if-then-else is a control statement that controls the flow of a program and doesn’t return any value. Otherwise, the compiler would give a time exception.

Ternary operator can be used in place of if-then-else statement where a variable requires to assign value based on the condition.

Nested Ternary Operators

Like, a nested if-else statement, one can also use multiple ternary operators in a nested manner.
public class TernaryOperator {

public static void main(String[] args) {
Scanner inputReader = new Scanner(System.in);
System.out.print("Please enter your age : ");
int voterAge = inputReader.nextInt();
String msg = voterAge < 18 ? (voterAge<13)? "you are a baby": "you are teenager" : "You can vote";
System.out.println(msg);
}


}

The above code can be explained as,

  • If entered age is greater than 18, then statement after “:” would be evaluated and a falsy statement returned, which is “you can vote”.
  • If entered age is lower than 18, then another ternary operator, followed by ?, would be evaluated
  • If inner condition which is (voterAge<13) evaluated as true, then “you are a baby” would be printed
  • Otherwise,  falsy statement of nested ternary operator would be executed.

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