What does the question mark mean in java

The question mark operator in Java is a ternary operator used for conditional expressions. The syntax is: result = (condition) ? true_value : false_value; If condition is true, result is equal to true_value, otherwise it is equal to false_value. Features include: simplifying conditional judgment, replacing if-else statements, can be nested, and widely used for condition checking, assignment and data conversion.

Question mark operator in Java

Question mark operator? is a Important operator, used in conditional expressions. It is a ternary operator consisting of three operands: a conditional expression, a truth expression, and a false expression.

Syntax:

<code>result = (condition) ? true_value : false_value;</code>

Meaning:

• If condition is true, then result is equal to true_value.
• If condition is false, then result is equal to false_value.

Example:

<code class="java">int age = 20;
String message = (age >= 18) ? "成年人" : "未成年人";
System.out.println(message); // 输出: 成年人</code>

In this example, condition is age >= 18, if age is greater than or equal to 18 years old, the result is assigned true_value ("adult"), otherwise it is assigned false_value (" minor").

Features:

• The question mark operator is a concise conditional judgment method.
• It can replace if-else statements and simplify the code.
• The question mark operator can be used nested to achieve more complex conditional judgments.
• Due to its characteristics, the question mark operator is widely used in Java, including condition checking, assignment and data conversion.

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