通过在 main 方法中接受 integer 来打印树

Question

I'm trying to print a tree by accepting an integer into the main method for an intro programming class. If the number is positive, accept it. If it is negative, print a statement and terminate the program.

The program runs perfectly. However, I am not allowed to print within the named method (printTriangle()).

What would the logical change in the order of code be to keep the printing statements solely in the main method()?

I have provided the code and output below for your convenience.

Thanks!

package triangletest;

import java.util.Scanner;

public class triangletest {

    public static void main(String[] args) {
        System.out.print("Enter the number of lines: ");

        Scanner scanner = new Scanner(System.in);

        int input = scanner.nextInt();

        scanner.close();

        if (input > 0) {
            printTriangle(input);
        } else {
            System.out.print("Number of lines is negative. Exiting");
        }
    }

    static void printTriangle(int input) {
        for (int i = 1, triangle = 1; i <= input; i++, triangle += 1) {
            for (int space = input; space > i; space--)
                System.out.print(" ");

            for (int x = 1; x <= triangle; x++)
                System.out.print("* ");

            System.out.println();
         }
    }
}

Output:

Enter the number of lines: 
5

Answer 1

Just copy the code which is inside in the printTriangle method into the place where you call printTriangle method.

    public static void main(String[] args) {
        System.out.print("Enter the number of lines: ");
        Scanner scanner = new Scanner(System.in);
        int input = scanner.nextInt();
        scanner.close();
        if (input > 0) {
            for(int i = 1, triangle = 1; i <= input; i++, triangle += 1)
            {
                    for(int space = input; space > i; space--)
                        System.out.print(" ");
                    for(int x = 1; x <= triangle; x++)
                        System.out.print("* ");
                    System.out.println(); 
            }
        }
        else 
        {
            System.out.print("Number of lines is negative. Existing");
        }
    }