如何在满足条件后从循环中断开 [英] How to break from a loop after the condition is met

问题描述

我一直试图在过去一小时内摆脱这个循环并继续，因为已经满足了我的条件一次。我的应用程序几乎读取了一系列行并分析它然后打印所述的变量。线条外观如何（不包括。）：

Hi I have been trying for the past hour to break from this loop and continue since already met my condition once. My application pretty much reads a serie of lines and analyzes it and then prints the variable stated. An example of how the lines look like (the . are not included):

• 10 c = 9 + 3


• 20 a = c + 1


• 30 print c


• 40 goto 20


• 50结束

• 10 c = 9+3
• 20 a = c+1
• 30 print c
• 40 goto 20
• 50 end

它做的一切正确，当它到达第40行时按预期进入第20行，但我希望它去第50行已经进入第40行了一次。以下是此部分的代码：

It does everything right, when it gets to line 40 goes to line 20 as expected, but i want it to go to line 50 since already went to line 40 once. Here is my code for this part:

while(booleanValue)
{
    if(aString.substring(0, 4).equals("goto"))
    {
        int chosenLine = Integer.parseInt(b.substring(5));
        if(inTheVector.contains(chosenLine))
        {
            analizeCommands(inTheVector.indexOf(chosenLine));
            i++;
        }
        else
        {
            System.ou.println("Line Was Not Found");
            i++;
        }
    }

    else if(aString.substring(0, 3).equals("end"))
        {
            System.out.println("Application Ended");
            booleanValue = false;
        }
}

推荐答案

使用一旦满足条件， break 语句就会完全打破循环。 Pol0nium建议使用 continue 是不正确的，因为它只停止循环的当前迭代。

Use the break statement to break out of a loop completely once your condition has been met. Pol0nium's suggestion to use continue would not be correct since that stops the current iteration of the loop only.

while(foo)
{
    if(baz)
    {
        // Do something
    }
    else
    {
        // exit condition met
        break;
    }
}

所有这些都说过，好的形式决定了你想要干净的进入和退出点，以便观察者（也许你自己，以后重新访问代码）可以轻松地遵循其流程。考虑改变控制while循环本身的布尔值。

All this having been said, good form dictates that you want clean entry and exit points so that an observer (maybe yourself, revisiting the code at a later date) can easily follow its flow. Consider altering the boolean that controls the while loop itself.

while(foo)
{
    if(baz)
    {
        // Do something
    }
    else
    {
        // Do something else
        foo = false;
    }
}

如果由于某种原因，你无法触摸控制while循环的布尔值，你只需要复制带有一个标志的条件来专门控制你的while：

If, for some reason, you can't touch the boolean that controls the while loop, you need only compound the condition with a flag specifically to control your while:

while(foo && bar)
{
    if(baz)
    {
        // Do something
    }
    else
    {
        // Do something else
        bar = false;
    }
}

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