逻辑或表达式c ++ [英] logical or expression c++

问题描述

我在C ++中使用逻辑OR运算符时遇到问题。问题出现，如果左侧是真的，则不评估右侧表达式。我有两个deque-s，我需要popLeft从他们一段时间，但如果我可以从第一个deque pop，我不会从第二个pop，因为没有评估，通过OR运算符。我如何克服这个问题。下面是一段代码：

I have a problem using the Logical OR operator in C++. The problem is coming that the right-side expression is not evaluated if the left-side is true. I have two deque-s and I need to popLeft from them with a while, but if I can pop from the first deque, I don't pop from the second because is not evaluated, by the OR operator. How can I overcome this problem. Here is the piece of code:

while( D.popLeft( k ) || E.popLeft( m ) )
{
    if( k < m )
    {
      C.pushRight( k );
      E.pushLeft( m );
    }
    else
    {
      C.pushRight( m );
      D.pushLeft( k );
    }
}

推荐答案

您要保留 || （而不是使用&& ），您可以分别评估： / p>

Assuming you want to keep your || (and not use a &&), you can evaluate separatly:

bool canPopE = E.popLeft( m );
bool canPopD = D.popLeft( k );
bool canPop = canPopD || canPopE;

while( canPop )
{
    if( k < m )
    {
      C.pushRight( k );
      E.pushLeft( m );
    }
    else
    {
      C.pushRight( m );
      D.pushLeft( k );
    }

    canPopE = E.popLeft( m );
    canPopD = D.popLeft( k );
    canPop = canPopD || canPopE;
}

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