版权声明: https://blog.csdn.net/xichengqc/article/details/88538523
坐标,某大型互联网公司,有个小伙伴发来一段代码,因源码涉及公司,处理之后如下:
for (flag = true; father instanceof Son; father = ((Son) father).mfather) {}
苦思不得其解,于是写了个demo,测试结果之后分析如下:
package com.xicheng.validator;
/**
* @author xichengxml
* @date 2019/3/7 16:45
*/
public class Main {
public static void main(String[] args) {
Son son = new Son();
son.mfather = new Son();
magicCode(son, false);
son.mfather = new Father();
magicCode(son, false);
}
/**
* 对这段魔性代码做个解释,进行了两个赋值操作,这个需要了解for循环的执行机制:
* 第一个语句是赋值语句;第二个语句是判断语句,如果为true则一直执行,直到为false退出;
* 第三个语句是赋值语句
*
* 所以上述的解释为:首先对flag赋值,然后判断father的类型,一直循环到不是son类型,把值
* 赋给father
* @param father
* @param flag
*/
private static void magicCode(Father father, boolean flag) {
int count = 0;
for (flag = true; father instanceof Son; father = ((Son) father).mfather) {
count++;
}
System.out.println("loop times:" + count);
System.out.println(flag);
if (father == null) {
System.out.println("null");
} else {
System.out.println(father.getClass());
}
}
static class Father {
}
static class Son extends Father {
Father mfather;
}
}