Question

我只使用了整个程序中的一部分，但我百分之百肯定它在于这种方法。

public void draw() 
{
    int count;
    int arrowHeadRight = getIndentationLevel() 
            + getBaseLength() / 2;
    for (count = 0; count < arrowHeadRight; count++)
    {
        System.out.print(' ');
    }
    System.out.println(drawingCharacter);
    int baseAtCenter = getBaseLength() / 2 - 1;
    int arrowHeadLeft = 1;
    for (count = 1; count <= baseAtCenter; count++)
    {
        for (count = 0; count < arrowHeadRight--; count++)
        {
            System.out.print(' ');
        }
        System.out.print(drawingCharacter);
        for (count = 0; count < arrowHeadLeft; count++)
        {
            System.out.print(' ');
        }
        System.out.print(drawingCharacter);
        arrowHeadLeft = arrowHeadLeft + 2;
    }
    for (count = 0; count < arrowHeadRight--; count++)
    {
        System.out.print(' ');
    }
    for (count = 1; count <= getBaseLength(); count++)
    {
        System.out.print(drawingCharacter);
    }
    System.out.print("\n");
    //Arrow Shaft
    for (count = 1; count <= shaftLength; count++)
    {
        for (count = 0; count < arrowHeadRight; count++)
        {
            System.out.print(' ');
        }
        System.out.println(drawingCharacter);
    }
}

现在假设for循环中的所有变量都大于count变量，那么会出现无限循环？我已经检查了很多次，以至于我的眼睛受伤了，看了一双新鲜的东西会有所帮助。

Answer 1

这是你的无限循环：

for (count = 1; count <= shaftLength; count++)
    {
        for (count = 0; count < arrowHeadRight; count++)
        {

每次内循环终止时，count将等于arrowHeadRight。如果arrowHeadRight <= shaftLength那么外部循环永远不会终止。

Answer 2

这是带有问题的代码的一部分：

for (count = 1; count <= shaftLength; count++)
{
    for (count = 0; count < arrowHeadRight; count++)
    {
        System.out.print(' ');
    }
    System.out.println("drawingCharacter");
}

你正在开始一个索引为count=1的for循环，然后在它内部开始另一个循环，使索引count保持为0.在内循环之后，count将等于arrowHeadRight ，而不是进入循环时的情况。

你的整个方法都充满了类似的例子。

解决方案是在使用嵌套for循环时使用不同的索引变量：

for (count = 1; count <= shaftLength; count++)
    {
        for (int count2 = 0; count2 < arrowHeadRight; count2++)
        {
            System.out.print(' ');
        }
        System.out.println(drawingCharacter);
    }

找不到无限循环，但它正在运行？

2 个答案: