为什么这个C++代码失败了？

Question

我有以下代码

#include <iostream>
#include <vector>

using namespace std;

int distance(vector<int>& set1, vector<int>& set2) {
    int distance = 0;

    unsigned int i1 = 0;
    unsigned int i2 = 0;
    while(i1 < set1.size() && i2 < set2.size()) {
        if(set1[i1] == set2[i2]) {
            ++i1; ++i2;
        } else {
            ++distance;
            set1[i1] < set2[i2] ? ++i1 : ++i2;
        }
    }

    unsigned int zero = 0;
    distance += std::max(set1.size() - i1, zero) + std::max(set2.size() - i2, zero);
}

int main() {
    vector<vector<int> > frequent_sets;
    vector<int> vector3;
    vector3.push_back(1);vector3.push_back(2);vector3.push_back(3);
    vector<int> vector2;
    vector2.push_back(1);vector2.push_back(2);

    frequent_sets.push_back(vector3);
    frequent_sets.push_back(vector3);
    frequent_sets.push_back(vector2);
    frequent_sets.push_back(vector3);


    for(vector<vector<int> >::iterator itouter = frequent_sets.begin(); itouter != frequent_sets.end(); ++itouter)
        for(vector<vector<int> >::iterator itinner = (itouter + 1); itinner != frequent_sets.end(); ++itinner)
            if(distance(*itinner, *itouter) == 0) {
                cout << "Hey" << endl;
            }
}

当我尝试编译时,我收到错误:

使所有建筑物的文件:../src/TestIterator.cpp调用:GCC C++编译器的g ++ -O0 -g3 -Wall -c -fmessage长度= 0 -MMD -MP -MF "SRC/TestIterator.d" -MT"SRC /TestIterator.d "-o "的src/TestIterator.o"" ../src/TestIterator.cpp" /usr/include/c++/4.3/bits/stl_iterator_base_types.h:在实例化'的std :: iterator_traits>>' :../src/TestIterator.cpp:50:
错误:从这里/usr/include/c++/4.3/bits/stl_iterator_base_types.h:133实例没有类型在"类性病名为"的iterator_category" ::矢量

'make:***[src/TestIterator.o]错误1

为什么是这样？当我distance(*itouter, *itinner) == 0用itinner->size() == itouter->size()代码替换正在编译并运行正常.

Answer 1

你的distance功能与中的一个冲突std.这就是为什么通常不建议using namespace std;您编写代码.尝试删除或将您的功能重命名为my_distance.