Question

我不是一名专业的c++程序员。我试图编写一个程序来显示给定输入字符串的所有可能的排列，假设字符串包含重复的字符。这是我到目前为止编写的代码：

我的代码的最新更新（permutation.cpp）：

#include <iostream>
#include <fstream>
#include <cstring>
#include <string>
#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include <list>
#include <set>
#include <iterator>
#include <sstream>
#include <cstdlib>
using namespace std;

//factorial function 
int factorial(int n){
    if (n==0) return 1;
    else{
       return n*factorial(n-1);
    }
}


int main (int argc, char *argv[]) {
   srand ( time(NULL) ); //initialize the random seed
   char* text;
   std::set<char> mySwapList;

   if ( argc < 1 )
   {
       cout << endl << "Please write a word in the following of the command line" << endl << endl;
       return 1;
   }
   else if ( argc != 2 ) // argc should be 2 for correct execution
   {  // We print argv[0] assuming it is the program name
       strcpy (text,argv[1]);
       cout<<endl<<"usage: "<< argv[0] <<" to compute all the permutations \n"<<endl;
       return 1;
   }   
   int ss=sizeof(text);
   int length = ss;
   int k=0;
   cout << "length of the word:"<<endl<< length<<endl;
   int total=factorial(length);
   while (k< total)
   { 
      char arr[ss];
      int index=0;
      stringstream ssin(text);
      while (ssin.good() && index<ss){
      ssin>>arr[index];
      ++index;
   }
      std::list<char> word(arr, arr+ss); 
      std::list<char> mylist;
      unsigned int j=0;
      while (j < length)
      {
           int n=word.size();
           int RandIndex = rand() % n;
           std::list<char>::iterator vi= word.begin();
           std::advance(vi,RandIndex);      
           std::list<char>::iterator iter= mylist.begin();
           mylist.insert(iter,*vi);
           word.remove(*vi);
           j++;
      }
      char str[ss];
      int ii=0;
      for (std::list<char>::iterator ix=mylist.begin(); ix!=mylist.end(); ++ix)
      {
          str[ii]=*ix;
          ii++;
      }
      string newWord = string(str);
      for (std::set<char>::iterator iss=mySwapList.begin(); iss!=mySwapList.end(); ++iss)
      {
      string w(1,*iss);
          if (newWord != w)
          {
             mySwapList.insert(newWord);
             k++;
      }
      }
   }
   //Loop for printing the list
   for(std::set<char>::iterator it = mySwapList.begin(); it != mySwapList.end(); ++it)
        cout << *it << " ";
    cout << endl;
   return 0;
}

编译代码时收到大量错误消息，包括：

更新错误：

permutation.cpp: In function ‘int main(int, char**)’:
permutation.cpp:82:39: error: no matching function for call to ‘std::set<char>::insert(std::string&)’
              mySwapList.insert(newWord);
                                       ^
permutation.cpp:82:39: note: candidates are:
In file included from /usr/include/c++/4.8/set:61:0,
                 from permutation.cpp:9:
/usr/include/c++/4.8/bits/stl_set.h:460:7: note: std::pair<typename std::_Rb_tree<_Key, _Key, std::_Identity<_Key>, _Compare, typename _Alloc::rebind<_Key>::other>::const_iterator, bool> std::set<_Key, _Compare, _Alloc>::insert(const value_type&) [with _Key = char; _Compare = std::less<char>; _Alloc = std::allocator<char>; typename std::_Rb_tree<_Key, _Key, std::_Identity<_Key>, _Compare, typename _Alloc::rebind<_Key>::other>::const_iterator = std::_Rb_tree_const_iterator<char>; std::set<_Key, _Compare, _Alloc>::value_type = char]
       insert(const value_type& __x)
       ^
/usr/include/c++/4.8/bits/stl_set.h:460:7: note:   no known conversion for argument 1 from ‘std::string {aka std::basic_string<char>}’ to ‘const value_type& {aka const char&}’
/usr/include/c++/4.8/bits/stl_set.h:497:7: note: std::set<_Key, _Compare, _Alloc>::iterator std::set<_Key, _Compare, _Alloc>::insert(std::set<_Key, _Compare, _Alloc>::const_iterator, const value_type&) [with _Key = char; _Compare = std::less<char>; _Alloc = std::allocator<char>; std::set<_Key, _Compare, _Alloc>::iterator = std::_Rb_tree_const_iterator<char>; std::set<_Key, _Compare, _Alloc>::const_iterator = std::_Rb_tree_const_iterator<char>; std::set<_Key, _Compare, _Alloc>::value_type = char]
       insert(const_iterator __position, const value_type& __x)
       ^
/usr/include/c++/4.8/bits/stl_set.h:497:7: note:   candidate expects 2 arguments, 1 provided
/usr/include/c++/4.8/bits/stl_set.h:517:2: note: template<class _InputIterator> void std::set<_Key, _Compare, _Alloc>::insert(_InputIterator, _InputIterator) [with _InputIterator = _InputIterator; _Key = char; _Compare = std::less<char>; _Alloc = std::allocator<char>]
  insert(_InputIterator __first, _InputIterator __last)
  ^
/usr/include/c++/4.8/bits/stl_set.h:517:2: note:   template argument deduction/substitution failed:
permutation.cpp:82:39: note:   candidate expects 2 arguments, 1 provided
              mySwapList.insert(newWord);

我无法弄清楚为什么会出现上述错误。有什么建议吗？

Answer 1

根据您要将string转换为list的问题标题。您无法直接执行此操作，但可以使用string迭代器：

#include <string>
#include <list>

int main(int argc, _TCHAR* argv[])
{
    std::string strTest = "hello!";
    std::list<char> list(strTest.begin(), strTest.end());

    return 0;
}

编辑：但根据您的代码，您根本不需要list。您可以在任何地方使用std::string。它有insert和[]个东西。它与vector<char>几乎相同，但具有其他功能。

Answer 2

您使用了未定义的类成员。试试strcpy_s()到char*数组。

Answer 3

在vector代码末尾使用mySwapList作为字符串容器解决了接受strings以及轻松访问{{1}的每个组件的问题}}。以下是原始问题的调试和工作版本：

vector

字符串的排列--error：没有用于调用'std :: set <char> :: insert（std :: string＆amp;）'的匹配函数

3 个答案: