C ++中的未知错误消息C2440

Question

因此，当我尝试在Unix中运行头文件时，出现错误消息“错误C2440：'初始化'：无法从'std :: vector <_Ty> *'转换为'std :: vector <_Ty>'”。 我想由于在allOperations中调用了“转换”而收到此错误，但是我不确定。 这是头文件：

#include <iostream>
#include <vector>
#include <string>
#include <fstream> //library for files
#include <cctype>
#include <algorithm>
#include <iterator>
#include <sstream>
#include <typeinfo>


using namespace std;

template <class T>
void alloc3DArray(T *** &x, int numberOfRows, int numberOfColumns,int numberOfDepth  )
{

 int i=0;
 int j=0;
 int k=0;


 // allocate an array for array of arrays
  x = new T ** [numberOfRows];


 // Allocate an array for each element of the first array
   for(i = 0; i < numberOfRows; i++)
    {

        x[i] = new T *[numberOfColumns];

  // Allocate an array of T for each element of this array
        for(j = 0; j < numberOfColumns; j++)
        {

            x[i][j] = new T [numberOfDepth];

   // Specify an initial value 
   for(int k = 0; k < numberOfDepth; ++k)
   {
    x[i][j][k] = -1;


   }


        }
    }

}

template <class T>
void dealloc3DArray(T *** &x, int numberOfRows, int numberOfColumns )

{
 // Check if it exeists 
 if(!x) //it does not exist
         exit(1);



    for (int i = 0; i < numberOfRows; ++i) 
    {
   for (int j = 0; j < numberOfColumns; ++j)

        {
    //delete innest
            delete [] x[i][j]; 
        }

   //delete columns
        delete [] x[i];
    }
 //delete first array
    delete [] x;
}

template <class T>
const vector<T>  allOperationsNotWorking(T *** &myArray1, T *** &myArray2,  T *** &myArray3,int numberOfRows, int numberOfColumns,int numberOfDepth  )

{
    int i=0;
 int j=0;
 int k=0;

    int size = numberOfRows * numberOfColumns * numberOfDepth; //find vector size
    vector<T> &myvector = vector<T>(size);// create a vector
    //vector<T>::const_iterator it;// const_iterator is faster than iterator
    for(i = 0; i < numberOfRows; i++)
   for(j = 0; j < numberOfColumns; j++)
    for(k = 0; k < numberOfDepth; k++){

     myArray3[i][j][k] =myArray1[i][j][k]+myArray2[i][j][k];

     myvector.push_back(myArray3[i][j][k]);


    }
     return myvector;


}

vector<string>  allOperationsString(string *** &myArray1, string *** &myArray2,  string *** &myArray3,int numberOfRows, int numberOfColumns,int numberOfDepth  )

{
    int i=0;
 int j=0;
 int k=0;

    int size = numberOfRows * numberOfColumns * numberOfDepth; //find vector size
    vector<string> myvector = vector<string>(size);// create a vector
    //vector<T>::const_iterator it;// const_iterator is faster than iterator
    for(i = 0; i < numberOfRows; i++)
   for(j = 0; j < numberOfColumns; j++)
    for(k = 0; k < numberOfDepth; k++){

     myArray3[i][j][k] =myArray1[i][j][k]+myArray2[i][j][k];

     myvector.push_back(myArray3[i][j][k]);


    }
     return myvector;


}

template <class T>
vector<T> isWord(vector<T> &stringVector, vector<T> &goodOnes,vector<T> &badOnes, vector<T> &dict)
{
    vector<int> strV;


 if (typeid(stringVector).name()== typeid(strV).name()){

 //if (typeid(stringVector)==int){
  ofstream badFile; //  declare and object as output file  using ofstream
  cout << " Illegal Vector" << endl;
  badFile.open ("hw1bout2.txt", ios::app);
  badFile << "Illegal Vector" << endl;
  badFile.close();
  return badOnes;
  }

 int i=0;
 int j=0;
 int FIRSTSIZE=stringVector.size();
 int SECONDSIZE = dict.size();
 std::string sInput="";
 std::string sDict="";

 sort(stringVector.begin(), stringVector.end());//sort() uses quicksort from the algorith library

  for(int i=0, j=0; i < FIRSTSIZE && j < SECONDSIZE; ){
   sInput=stringVector[i];


   std::transform(sInput.begin(), sInput.end(), sInput.begin(), std::toupper); //convert input word to upper

   sDict=dict[j];


   if(sInput.compare(sDict) == 0) {
   goodOnes.push_back(stringVector[i]); //write good word to vector

   i++;//advance one position in string vector
   j++;//advance one position in dictionary
    }

  else if(stringVector[i] < dict[j] && FIRSTSIZE < SECONDSIZE){// wrods did not match
   if (stringVector[i].size() >0) badOnes.push_back(stringVector[i]); //write bad word to vector if not empty string
   i++;//advance one position in string vector
   }

  else{
   j++;//advance one position in dictionary
    }
}



 return goodOnes;
}

template<class T >    
vector<string> isWord(vector<int> &stringVector, vector<string> &goodOnes,vector<string> &badOnes, vector<string> &dict)
{

 vector<int> strV;


 if (typeid(stringVector).name()== typeid(strV).name()){

  badOnes.push_back("Illegal Vector" );
 }
  return badOnes;

}

//template<class T>
vector<int>  allOperations(int *** &myArray1, int *** &myArray2,  int *** &myArray3,int numberOfRows, int numberOfColumns,int numberOfDepth  )

{
    int i=0;
 int j=0;
 int k=0;

    int size = numberOfRows * numberOfColumns * numberOfDepth; //find vector size
    vector<int> myvector = vector<int>(size);// create a vector
    //const vector<int>& myvector;
    //vector<int>::const_iterator it = myvector.begin();
    vector<int>::const_iterator it;// const_iterator is faster than iterator
    for(i = 0; i < numberOfRows; i++)
   for(j = 0; j < numberOfColumns; j++)
    for(k = 0; k < numberOfDepth; k++){

     myArray3[i][j][k] =myArray1[i][j][k]+myArray2[i][j][k];

     myvector.push_back(myArray3[i][j][k]);


    }
     return myvector;


}

Answer 1

从g ++（不是您发布的错误消息）获得的实际错误消息非常清楚地表明， std::transform的最后一个参数是重载函数的名称。

由于该参数用于模板参数推导，因此编译器无法选择任何重载。 我们将通过在强类型上下文中命名重载函数的集合来帮助实现这一目标：

char (*transformation_fn)(char) = &std::toupper;
std::transform(sInput.begin(), sInput.end(), sInput.begin(), transformation_fn);

进行此更改后， 代码可以正确编译 。