[C ++尝试在循环内捕获

Question

我有具有以下一般结构的C ++程序

1st while (condition A == true)
  //some code for 1st loop

  2nd while (condition B == true)
    //some code for 2nd loop
    try
      //some code for try
    catch
      //condition B == false (supposed to leave 2nd loop and go back to first loop)

我希望它在出现异常时退出第二循环，并返回到第一循环，直到条件B再次出现。如上所述，它无法正常工作。似乎正在发生的是，代码被卡在catch中，再也不会离开它。

如何安排它以使其按需工作？

注意：条件A绝不为假。

Answer 1

将break关键字添加到捕获中

还要注意，您的b == false；那就是在检查b是否等于false，而不是设置b = false。

Answer 2

bool flag1 = true, flag2 = true;
while (flag1)
{
  // some work so that flag2 == true
  while (flag2)
  {
    try
    {

    }
    catch (...) // any exception happens
    {
        break;
    }
  }
}

Answer 3

1st while (condition A == true) 
  //some code for 1st loop 

  2nd while (condition B == true) 
    //some code for 2nd loop 
    try 
      //some code for try 
    catch 
    {
      //condition B == false (supposed to leave 2nd loop and go back to first loop) 
      break ;
    }

注意：即使在示例中，也请勿使用condition A == true之类的东西。最好使用while (condition A)。

Answer 4

您可以在catch块中调用break以逃脱第二个循环：

void foo(void) {
    bool A(true);
    while (A) {
        bool B(doSomething());
        while (B) {
            try {
                B = doSomethingElseThatMayThrow();
            } catch (...) {
                break;
            }
        }
     }
}

或者，您可以将第二个循环放在try块内：

void foo(void) {
    bool A(true);
    while (A) {
        bool B(doSomething());
        try { 
            while (B) {
                B = doSomethingElseThatMayThrow();
            }
        } catch (...) {}
    }
}