public class ShuiXian{
    public static void main(String[] args){
        int i=153;
        int j=i/100;
        int k=(i/10)%10;
        int n=i%10;
        if(i>=100&&i <1000){
            if(i==j*j*j+k*k*k+n*n*n){
              System.out.println(i+"是水仙花数!");
            }else{
              System.out.println(i+"不是水仙花数!");
            }
        }else{
            System.out.println("输入的不是三位数!");
        }
    }
}

------解决方案--------------------
Java code

public class Test {
　／／把0-9的n次方先算出来保存到一个数组里，每次用到的时候直接去取，避免多次运算，提高效率．
    private static final int[] arr = {0,1,8,27,64,125,216,343,512,729};
    public static void main(String[] args) { 
        System.out.println(isArmstrongNumber(153));
    } 
    
    public static boolean isArmstrongNumber(int n) { 
        int temp = n;
        while(temp!=0) {
            n -= arr[temp%10];
            temp/=10;
        }
        return n==0;
    } 
}