尝试打印 unordered_map

Question

我正在编写一个简单的程序来查找字谜。我正在使用散列 table，其中已排序的字符串作为键，未排序的字符串作为值。当我尝试打印 unordered_map（散列映射）时，它给了我这个错误。

Error 1 error C2675: unary '++' : 'std::string' does not define this operator or a conversion to a type acceptable to the predefined operator c:\program files (x86)\microsoft visual studio 12.0\vc\include\xhash 672 1

#include <iostream>
#include <list>
#include <cstdlib>
#include <map>
#include <string>
#include <vector>
#include <unordered_map>
#include <algorithm>
#include <cstring>



void Anagrams(std::vector<std::string> &v){

    std::unordered_map<std::string, std::string> wordTable;

    char sortedString[256];

    for (std::string tmp : v){

        strcpy(sortedString, tmp.c_str());

        std::sort(sortedString, sortedString + tmp.size());

        std::string backToString(sortedString);

        wordTable.insert(backToString, tmp);
    }

    std::cout << "Map contains" << std::endl;


    std::cout << "mymap's buckets contain:\n";
    for (unsigned i = 0; i < wordTable.bucket_count(); ++i) {
        std::cout << "bucket #" << i << " contains:";
        for (auto local_it = wordTable.begin(i); local_it != wordTable.end(i); ++local_it)
            std::cout << " " << local_it->first << ":" << local_it->second;
        std::cout << std::endl;
    }




}




int main()
{

    std::vector<std::string> words{ "debitcard", "badcredit", "cat", "act", "evils", "elvis" };

    Anagrams(words);



    return 0;


}

出于某种原因，它认为迭代器 "local_it" 是一个字符串。有人可以帮忙吗？

Answer 1

问题是 std::unorderd_map::insert() 函数采用 std::pair<key, value>，而不是 key, value:

 wordTable.insert(std::make_pair(backToString, tmp));

尝试打印 unordered_map

Trying to print an unordered_map

c++

iterator

hashmap

anagram