Java:通过调用方法打印三角形和空格

Question

我被这个问题困住了:

Printing stars and spaces

Define a method called printSpaces(int number) that produces the number of spaces specified by number. The method does not print the line break.

You will also have to either copy the printStars method your previous answer or reimplement it in this exercise template. Printing a right-leaning triangle

Create a method called printTriangle(int size) that uses printSpaces and printStars to print the correct triangle. So the method call printTriangle(4) should print the following: Sample output

>    *
>   **
>  ***
> ****

我无法让空间的东西在第一个问题上发挥作用，而且我完全迷失在制作递归三角形上。我看到很多答案都在使用 for 循环，但是我正在工作的类(class)希望它们作为方法完成。我无法理解如何正确翻译它。我用相反的方式得到了三角形:

public class Test072 {

    public static void main(String[] args) {
        printTriangle(4);
    }


    public static void printTriangle(int size) {
        int numSize = 0;
        while (numSize < size) {
            printStars(numSize);
            numSize++;
        }
    }

    public static void printStars(int number) {
        int numStar = 0;
        while (numStar <= number) {
            System.out.print("*");
            numStar++;
        }
        System.out.println();
    }
}

一旦我们开始添加空格，我就完全迷失了，不知道如何调用什么以及何时调用。我不知道如何按照他们的要求正确地将空间方法调用到三角形方法中。

Answer 1

这应该可以完成工作。

public static void printTriangle(int size) {
    int numSize = 0;
    while (numSize < size) {
        printSpaces(size - numSize - 1);
        printStars(numSize);
        numSize++;
    }
}
public static void printSpaces(int number) {
    int numSpaces = 0;
    while (numSpaces < number) {
        System.out.print(" ");
        numSpaces++;
    }
}
    public static void printStars(int number) {
        int numStar = 0;
        while (numStar <= number) {
            System.out.print("*");
            numStar++;
        }
        System.out.println();
    }
}