java - 如何在 java 中绘制带星号的半箭头？

Question

我正在上我的第一个 Java 类(class)，我正在尝试使用星号绘制一个半箭头。我应该使用嵌套循环，其中内部循环绘制 *s，外部循环迭代次数等于箭头底部的高度。我已经学习了 if-else、while 循环和 for 循环。

到目前为止，我已经能够为
的输入值正确绘制箭头箭头底部高度:5
箭头底部宽度:2
箭头宽度:4

当我尝试添加一个 while 循环作为外层循环时，程序超时。我很茫然。

我需要使用的下一个输入是 2、3、4。我的代码获取右基的高度 (2)，但不是宽度。

我需要的最后一个输入是 3, 3, 7。我的代码根本没有得到正确的结果。这是我目前所拥有的。

我应该使用什么样的循环来获得正确的宽度？

  Scanner scnr = new Scanner(System.in);
  int arrowBaseHeight = 0;
  int arrowBaseWidth  = 0;
  int arrowHeadWidth = 0;
  int i = 0;

  System.out.println("Enter arrow base height: ");
  arrowBaseHeight = scnr.nextInt();

  System.out.println("Enter arrow base width: ");
  arrowBaseWidth = scnr.nextInt();

  System.out.println("Enter arrow head width: ");
  arrowHeadWidth = scnr.nextInt();


  for (i = 1; i <= arrowBaseHeight; ++i) {
      // Draw arrow base (height = 3, width = 2)
      System.out.println("**");
  }

  // Draw arrow head (width = 4)
  System.out.println("****");
  System.out.println("***");
  System.out.println("**");
  System.out.println("*");

输出箭头的外观示例:

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

Answer 1

对于这个问题，您可能希望使用 for 循环，因为您知道它应该重复的确切次数。你知道这一点是因为用户输入了箭头每个部分的大小。

Scanner scnr = new Scanner(System.in);

int arrowBaseHeight = 0;
int arrowBaseWidth  = 0;
int arrowHeadWidth = 0;
int i = 0;

System.out.println("Enter arrow base height: ");
arrowBaseHeight = scnr.nextInt();

System.out.println("Enter arrow base width: ");
arrowBaseWidth = scnr.nextInt();

System.out.println("Enter arrow head width: ");
arrowHeadWidth = scnr.nextInt();

//Your code above | Below is the modified code

String ast = ""; //String ast will contain how many asterisk we want for the base width;

for (int x = 1; x <= arrowBaseWidth; x++) //Loop forms the base width of the arrow
{
    ast += "*"; //This adds as many asterisks as we need to make the base width. SO if they enter 4, we get 4 *;
}


for (i = 1; i < arrowBaseHeight; ++i) 
{   
    System.out.println(ast); //Prints out the base width, which is now a String object
}

int tempHeadWidth = arrowHeadWidth; //Added this tempHeadWidth variable since we will be modifying it directly and 
                                    //we don't want to modify the original data and variable (it will cause problems if we do.

for (int y = 1; y <= arrowHeadWidth; y++) 
{
    for(int z = tempHeadWidth; z > 0; z--) //This loop prints the amount of asterisks we need per line in the arrowHead
    {
        System.out.print("*");
    } 
    // Once the loop above is finished, the rest of the code will execute in the main for-loop and then scheck if it will run again.
    tempHeadWidth -= 1; //So we are lowering the tempHeadWidth by one so the next time it enters 
                        //the nested (2nd) for loop it will be one asterisk smaller

    System.out.println(); //This makes a new line to keep adding more stars for the next row 
}

此方法允许用户为箭头输入任意大小(当然，同时保持在 int 的值边界内)