错误：没有匹配的 function 调用 'recherche(std::vector >&, std::vector >::iterator, std::vector >::iterator, const char [10])'

Question

我收到此错误：错误：没有匹配的 function 调用 'recherche(std::vector >&, std::vector >::iterator, std::vector >::iterator, const char [10])'

错误：没有匹配的 function 调用 'recherche(std::__cxx11::list&, std::__cxx11::list::iterator, std::__cxx11::list::iterator, int)'

错误：没有匹配的 function 调用 'recherche(std::array&, std::array::iterator, std::array::iterator, double)'

#include<iostream>
#include<vector>
#include<array>
#include<list>
#include<algorithm>
#include<iterator>
#include<set>

using namespace std;

template <template<typename> class C, class InputIterator, typename A>
bool recherche(C<A> s, InputIterator debut, InputIterator fin, A n)
{
    InputIterator itr;
    for (itr = debut; itr != fin; itr++) {
        if(*itr == n){
            return 1;
        }}
    return 0;
}
int main(){
    vector<string> strVec = {"Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"};
    list<int> my_list = { 12, 5, 10, 9, 4, 90 };
    array<float, 5> arr = { 10.56, 20.99, 30.34, 40.12, 10.1 };
    
    cout << recherche(strVec, strVec.begin(), strVec.end(), "Wednesday") << endl;
    cout << recherche(my_list, my_list.begin(), my_list.end(), 90) << endl;
    cout << recherche(arr, arr.begin(), arr.end(), 30.34) << endl;
    
    return 0;
    }
}

Answer 1

std::vector接受两个模板参数，一个用于元素，一个用于分配器。 解决此问题的一种方法是在 function 中同时接受它们：

template <template<typename, typename> class C, class InputIterator, typename Elem, typename Alloc>
bool recherche(C<Elem, Alloc> s, InputIterator debut, InputIterator fin, Elem n)
{
    InputIterator itr;
    for (itr = debut; itr != fin; itr++) {
        if(*itr == n){
            return 1;
        }}
    return 0;
}

但是，您也可以通过利用所有 STL 容器实现的value_type来获取元素值类型：

template<class Vec, class Elem = Vec::value_type>
void foo(Vec v, Elem e) {
    // the element type is extracted in compile time. The only constraint is
    // that your container must implement value_type and all stl containers do so
    // Of course Vec is not necessarily a vector, it can be a list, an array, an unordered_map etc.
}