输入数字n，然后打印1到n之间的所有偶数平方

Question

I need help figuring out on how to output even numbers between 1 and N (n is a number entered by the user).

Here is what I have so far.

import java.util.*;

public class HelloWorld{

     public static void main(String []args){
         int n;
         int i = 0;

        Scanner scan = new Scanner(System.in);
        System.out.println("Enter a Number");
        n = scan.nextInt();

        for(i=1; i<n; i++){
            if(i%2==0)
            i = i*i;
            System.out.println(i);
        }    
    }
}

Now that prints out the wrong output. I would like to know how it gets from 4 to 16 and to 36.

Sample Input: 45

Expected Output:

4
16
36

What is it that I'm doing wrong?

Answer 1

You are already increasing the variable i in the for definition, you don't need to increase again inside for block. Also start from 2 and move on by adding 2 on each step for a more efficient implementation.

for(i=2; i*i<n; i+=2){
        System.out.println(i*i);
    }    

Answer 2

First, don't change the value of i inside the for loop. Instead of changing i to equal i*i , just print out i*i using the statement System.out.println(i*i) ; Secondly, you also forgot the curly brackets after your if statement.