Java switch：变量声明和作用域

Z时代
2024-01-10
分类：问答

Java编译器如何处理以下开关块？“ b”变量的范围是什么？

注意，“ b”变量仅在switch语句的第一个分支中声明。尝试在第二个分支中声明它也会导致“重复的局部变量”编译错误。

    int a = 3;
    switch( a ) {
    case 0:
        int b = 1;
        System.out.println("case 0: b = " + b);
        break;
    case 1:
        // the following line does not compile: b may not have been initialized
        // System.out.println("case 1 before: b = " + b);
        b = 2;
        System.out.println("case 1 after: b = " + b);
        break;
    default:
        b = 7;
        System.out.println("default: b = " + b);
    }