如何将pair <int,int>插入队列？

Question

我在将类型的对象插入pair<int, int>队列时遇到问题.我收到一个奇怪的错误,我不知道如何修复它.有人可以帮忙吗？以下是该方法的代码,后跟错误消息.前两个错误是针对插入,最后一个是用于使用operator=,帮助也是值得赞赏的.谢谢!

pair<int,int>* bfSpanningTree(int theVertex)
{
    queue< pair<int,int> > pairq;
    queue<int> nodeq;
    if(linkedAdjacencyList[theVertex]->value == theVertex && linkedAdjacencyList[theVertex]->adj != NULL)
    {
        Node* whereto;
        whereto = linkedAdjacencyList[theVertex]->adj;
        while(whereto->adj != NULL)
        {
            pairq.push(pair< &whereto->value, &whereto->adj->value >);
            nodeq.push(whereto->value);
            whereto = whereto->adj;
        }
        while(!nodeq.empty())
        {
            whereto = linkedAdjacencyList[theVertex]->adj;
            while(whereto->adj != NULL)
            {
                pairq.push(pair<&whereto->value, &whereto->adj->value>);
                whereto = whereto->adj;
            }
        }
    }
    int i = 0;
    pair<int,int>* retVal;
    pair<int,int> tree[pairq.size()];
    while(!pairq.empty())
    {
        tree[i] = pairq.pop();
        i++;
    }
    retVal = tree;
    return retVal;
}

~UndirectedGraph()
{
    for (int i = 0; i < numVerticies; i++)
        delete[] linkedAdjacencyList[i];
}

错误:

hw8.h:181:错误:模板参数数量错误(1,应为2)

/usr/include/c++/4.4/bits/stl_pair.h:67:错误:提供 ‘template<class _T1, class _T2> struct std::pair’

hw8.h:190:错误:模板参数数量错误(1,应为2)

/usr/include/c++/4.4/bits/stl_pair.h:67:错误:提供 ‘template<class _T1, class _T2> struct std::pair’

hw8.h:200:错误:不匹配‘operator=’in‘tree[i] = pairq.std::queue<_Tp, _Sequence>::pop [with _Tp = std::pair<int, int>, _Sequence = std::deque<std::pair<int, int>, std::allocator<std::pair<int, int> > >]()’

/usr/include/c++/4.4/bits/stl_pair.h:68:注意:候选人是: std::pair<int, int>& std::pair<int, int>::operator=(const std::pair<int, int>&)

Answer 1

像这样的代码行:

pairq.push(pair< &whereto->value, &whereto->adj->value >);

应该看起来像:

pairq.push(make_pair(whereto->value, whereto->adj->value));

或者如果value成员不是类型int:

pairq.push(pair<int,int>(whereto->value, whereto->adj->value));

最后,queue::pop()不返回任何内容,所以你可能想要:

tree[i] = pairq.front();
pairq.pop();