如何让我的代码失去开头的空格？

Question

主要问题：输出中存在额外的空格

我希望我的代码从我记下的输入中打印出数字的一步。我的主要问题是空白。我需要输出在一开始就少一个空格。

从我的 System.out.print() 中删除“”；更改循环 反转循环分段

import java.util.Scanner;

public class PatternTwo {

    public static void main(String[] args) {

        Scanner scan = new Scanner(System.in);

        System.out.println("Please enter a number 1...9 : ");

        int num = scan.nextInt(); 

        for(int i = 1; i <= num; ++i) { 

        for(int j=2*(num-i); j>=0; j--)

        {

        if (num <= 1)

            System.out.print("");

        else if (num > 1)

            System.out.print(" ");

        }

        for(int j = i; j >= 1; --j) {

        System.out.print(" " + j); 

        }

        System.out.println();

        }

    }

}

}```

I would like the result to be 

Please enter a number 1...9 :  2

  1

 2

Instead of:

Please enter a number 1...9 :  2

   1

  2

Answer 1

这里有两个问题：j >= 0应该改为j > 0您应该避免在以下情况下打印空白区域：j == ipublic static void main(String[] args) {&nbsp; &nbsp; Scanner scan = new Scanner(System.in);&nbsp; &nbsp; System.out.println("Please enter a number 1...9 :");&nbsp; &nbsp; int num = scan.nextInt();&nbsp;&nbsp; &nbsp; scan.close();&nbsp; &nbsp; for (int i = 1; i <= num; i++) {&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; for (int j = 2*(num-i); j > 0; j--)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (num > 1)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; System.out.print(" ");&nbsp; &nbsp; &nbsp; &nbsp; for (int j = i; j >= 1; j--) {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if (j != i)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; System.out.print(" ");&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; System.out.print(j);&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; System.out.println();&nbsp; &nbsp; }}我收到以下输出num = 5：Please enter a number 1...9 :5&nbsp; &nbsp; &nbsp; &nbsp; 1&nbsp; &nbsp; &nbsp; 2 1&nbsp; &nbsp; 3 2 1&nbsp; 4 3 2 15 4 3 2 1

Answer 2

尝试添加一个第一次跳过空格的 if 语句，例如：for(int j = i; j >= 1; --j)&nbsp;{&nbsp; &nbsp; if(j == i)&nbsp; &nbsp; &nbsp; &nbsp; System.out.print(j);&nbsp; &nbsp; else&nbsp; &nbsp; &nbsp; &nbsp; System.out.print(" " + j);&nbsp;}