如何仅使用for循环生成奇数

Question

I must produce the following output using only nested for loops:

-----1-----
----333----
---55555---
--7777777--
-999999999-

I cannot use any while or if statements

Here is my code:

public static void printDesign() {
    //for loop for the number of lines
    for (int i = 1; i <= 9; i++) {
        
        //for loop for the left -
        for (int j = 1; j <= 6 - i; j++) {
            System.out.print("-");
        }
        
        //for loop for #'s
        for (int k = 1; k <= 2 * i - 1; k++) {
            System.out.print(i);
        }
        
        //for loop for the right -
        for (int x = 1; x <= 6 - i; x++) {
            System.out.print("-");
        }
        System.out.println();
    }    
}

This is what it produces:

-----1-----
----222----
---33333---
--4444444--
-555555555-
66666666666
7777777777777
888888888888888
99999999999999999

How can I get it to only produce the odd numbers?

Answer 1

Your solution is very close to the correct one. Simply change the step of i in the outer cycle.

Answer 2

for (int i = 1; i <= 9; i += 2) {
   for (int j = 0; j < (9 - i) / 2; j++) System.out.print('-');
   for (int k = 0; k < i; k++) System.out.print(i);
   for (int l = 0; l < (9 - i) / 2; l++) System.out.print('-');
   System.out.println();
}

Output:

----1----
---333---
--55555--
-7777777-
999999999

Answer 3

Change your first for-loop increment value from 1 to 2.

for (int i = 1; i <= 9; i+=2){}

Answer 4

Sounds like a homework assignment. But I'll give you the hint that the key is in the "for(" line.