在看一本08年出版的书的时候,看到了这样一个问题,感觉答案很奇怪:
public class demo_p22 {public static void main(String args[]){int sCook=1,sFish=2;//各技能标记character ch1=new character();if(ch1.haveSkill(sCook))System.out.println(ch1.name+"会烹饪");else System.out.println(ch1.name+"不会烹饪");if(ch1.haveSkill(sFish))System.out.println(ch1.name+"会钓鱼");else System.out.println(ch1.name+"不会钓鱼");System.out.println("-------------------");ch1.output();System.out.println( ch1.haveSkill(sCook));}
}
class character {String name ="smith";String sex="m";int skill=0;boolean haveSkill (int skillCode){return ((this.skill&skillCode)==skillCode);}void output(){System.out.println(this.skill);}
}
C:\Java\jdk-17.0.11\bin\java.exe "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2022.1.3\lib\idea_rt.jar=2317:C:\Program Files\JetBrains\IntelliJ IDEA 2022.1.3\bin" -Dfile.encoding=UTF-8 -classpath C:\Test\classDemo\out\production\classDemo Java_zhangyu.demo_p22
smith不会烹饪
smith不会钓鱼
-------------------
0
false进程已结束,退出代码0
通过对比,果然是书中答案是错误的;
总结:
1.第一次看到“|”,内心很疑惑,也有一点畏难。认真看了一下,其实就是this.skill==0|1;
void learnSkill(int skillCode){this.skill=this.skill|skillCode;}
return ((0&1)==1);
boolean haveSkill (int skillCode){return ((this.skill&skillCode)==skillCode);}
2. &,|,^