Question

所以我给了它最好的一击，我真的在试图想出一个解决方案来解决这个问题。之前已经在这里询问过这类问题，但这一次有点麻烦。

所以我应该打印左箭头，例如：

  public class Arrow {

  public static void main(String[] args) {

  int n = 0;

  if (args.length < 1) {

     System.out.println("Input a value.");
     System.exit(0);  

  }      
  else {

     n = Integer.parseInt(args[0]);

  }

  for (int rows = 1; rows <= n; rows++) {//This tells how many lines to print (height)

    for (int numSpaces = 0; numSpaces < (n - rows); numSpaces++) {//Prints spaces before the '*'
        System.out.print("  ");
    }

    for (int numStars = 0; numStars < rows; numStars++) { //Prints the " " first in each line then a "*".  
        System.out.print("*");
    }

    System.out.println(""); //Next Line         

  }

  for (int rows = 1; rows <= n; rows++) {//This tells how many lines to print (height)

    for (int numSpaces = n; numSpaces > (n - rows); numSpaces--) {//Prints spaces before the '*'
        System.out.print("  ");
    }

    for (int numStars = n; numStars > rows; numStars--) { //Prints the " " first in each line then a "*".  
        System.out.print("*");
    }

    System.out.println(""); //Next Line         

    }       

 }

}

        *
       **
      ***
     ****
    *****
     ****
      ***
       **
        *

现在我遇到的问题是箭头应该有一个中间部分伸出后端，相当于n +（n - 1）的长度。我无法弄清楚如何做到这一点，因为我是循环的新手，我花了2个小时的时间来试图做到这一点。

可以请一些善意的灵魂请求帮助我帮助我。

由于

Answer 1

我刚刚在你的第一个大for循环中添加了一个if块。留意// This is where the tail of the arrow starts和// This is where the tail of the arrow ends。我现在将尾长保持为2*n，您可以根据需要更改它，比如说3*n或其他内容。

if检查有助于评估条件并采取相应措施：

  for (int rows = 1; rows <= n; rows++) {//This tells how many lines to print (height)

    for (int numSpaces = 0; numSpaces < (n - rows); numSpaces++) {//Prints spaces before the '*'
        System.out.print("  ");
    }

    for (int numStars = 0; numStars < rows; numStars++) { //Prints the " " first in each line then a "*".  
        System.out.print("*");
    }
    // This is where the tail of the arrow starts
    if(rows==n) { 
        // Decide the length of the tail of the arrow here. It is currently 2*n below
        for(int arrowLength = 1; arrowLength <= 2*n; arrowLength++) {
            System.out.print("*");
        }
    }
    // This is where the tail of the arrow ends
    System.out.println(""); //Next Line         
  }

输入为10：

                  *
                **
              ***
            ****
          *****
        ******
      *******
    ********
  *********
******************************
  *********
    ********
      *******
        ******
          *****
            ****
              ***
                **
                  *

将*打印为java中的箭头

1 个答案: