Usage of switch case statement in java

Usage of switch-case statement in Java

In Java, the switch-case statement is a multi-way selection statement used to Values ​​execute different blocks of code. It is similar to the switch statement in languages ​​such as C and C.

Syntax:

<code class="java">switch (variable) {
    case value1:
        // 代码块 1
        break;
    case value2:
        // 代码块 2
        break;
    ...
    default:
        // 默认代码块
}</code>

Usage:

1. Variable type: variable can be byte, short, int, char, String, or an enumeration type.
2. Value comparison: The value following case must match the value of variable.
3. Code block: The code block to be executed is specified after each case.
4. break statement: The break statement is used to exit the switch statement immediately after executing a block of code. If there is no break statement, execution will continue with subsequent case blocks.
5. default block: The default block is optional and is used to execute code when no other case matches.

Example:

<code class="java">int dayOfWeek = 3;

switch (dayOfWeek) {
    case 1:
        System.out.println("星期一");
        break;
    case 2:
        System.out.println("星期二");
        break;
    case 3:
        System.out.println("星期三");
        break;
    default:
        System.out.println("未知的星期");
}</code>

Advantages:

• The code is highly readable and easy to maintain.
• Performance is better than if-else statements because the compiler can optimize switch-case statements.

Note:

• Each case value must be a constant, not a variable.
• case Value cannot be repeated.

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