做例外

Question

我不知道为什么这个例外不起作用......

import java.util.*;

public class a {
    public static void main(String[] args) {
        Scanner a = new Scanner(System.in);
        int x; 
        x=a.nextInt();
        if( x < 5) {
            System.out.print("This is if statement");
        }else if(x<3){
            System.out.print("This is else if statement");
        }else{
           System.out.print("This is else statement");
        }
        a.close();
    }
}

Answer 1

我认为你的意思是Condition而不是Exception，但是，你没有得到预期结果的原因是因为if-statements

if( x < 5) { // any input less than 5 will execute this if statement and will NOT proceed to the next blocks
     System.out.print("This is if statement");
}else if(x<3){ // this is not reachable because the first if statement will catch all inputs less than 5 INCLUDING those less than 3
     System.out.print("This is else if statement");
}else{
     System.out.print("This is else statement");
}

要解决此问题，只需修改if-statements的优先级，如下所示：

if( x < 3) { // this should come first
     System.out.print("This is if statement");
}else if(x<5){
     System.out.print("This is else if statement");
}else{
     System.out.print("This is else statement");
}