q879175707 2017-02-16 02:32 采纳率: 100%
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java基础中作用域问题

public class NestVar {

public static void main(String[] args) {
    int count;
    for (count = 0; count < 10; count = count + 1) {
        System.out.println("This is count:" + count);

        for (count = 0; count < 2; count++){
            System.out.println("This is count:" + count);
            System.out.println("This program is in error!!!");
        }
    }
}

}
这段代码的输出结果是:

This is count:0

This is count:0

This program is in error!!!

This is count:1

This program is in error!!!

This is count:3 // 为什么会是3呢

This is count:0 // 为什么会初始化变量

This program is in error!!!

This is count:1

This program is in error!!!

This is count:3

This is count:0

This program is in error!!!

This is count:1

This program is in error!!!

This is count:3

This is count:0

This program is in error!!!

This is count:1

This program is in error!!!

This is count:3

This is count:0

This program is in error!!!

This is count:1

This program is in error!!!

This is count:3

......(死循环)

请大神不吝赐教!最好解释的详细点。新人没有币。

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3条回答 默认 最新

  • 强化脑细胞 2017-02-16 02:55
    关注

    代码执行流程:
    1.执行第一层for循环,此时count值是0,0<10,执行for循环体打印This is count:0
    2.(此处是死循环)进入第二层循环,又将count重新初始化为0,0<2,打印This is count:0
    This program is in error!!! 打印之后 count值++ , 此时count值是1,1<2,
    打印This is count:1
    This program is in error!!! 之后count++ , count此时值为2,2不<2 ,第二层循环不执行,此时执行第一层循环的count = count + 1;
    此时count值是3,之后再次进入第一层循环的条件判断,3<10 ,执行循环体,This is count:3 然后在进入第二层循环 即再次从2.处循环...... 因此是个死循环

    本回答被题主选为最佳回答 , 对您是否有帮助呢?
    评论
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