help me with an io problem

[jinanzhaorenbo]

my program is basically to ask the user to input the number of input files and the name of each input file. Then, it concatenates every line of input files with same line number into a complete line. All the complete lines are output into an output file with name specified by the user.
The following is my code:

  1 #include <iostream>
  2 #include <fstream>
  3 #include <string>
  4 using namespace std;
  5
  6 int main(){
  7
  8     int fileNum;
  9     string inFileName, outFileName;
 10
 11     cout << "How many input files: ";
 12     cin >> fileNum;
 13
 14     //create an array of ifstream objects
 15     ifstream *inFilePtr = new ifstream[fileNum];
 16
 17     //open every input file
 18     for (int i = 0; i < fileNum; i++){
 19         cout << "Name of file NO." << (i + 1) << ": ";
 20         cin >> inFileName;
 21         (inFilePtr[i]).open(inFileName);
 22     }
 23
 24     //create an ofstream object
 25     cout << "Specify the name of output file: ";
 26     cin >> outFileName;
 27     ofstream oFile;//(outFileName);
 28     oFile.open(outFileName);
 29
 30     //create an array of strings to store lines in each file
 31     string *stringPtr = new string[fileNum];
 32
 33     //concatenate each line
 34     while (getline(*inFilePtr, *stringPtr)){
 35        oFile << *stringPtr << '\t';
 36        for (int i = 1; i < fileNum; i++){
 37            getline(inFilePtr[i], stringPtr[i]);
 38            oFile << stringPtr[i] << '\t';
 39        }
 40        oFile << endl;
 41     }
 42
 43     //close input and output files
 44     for (int i = 0; i < fileNum; i++)
 45         inFilePtr[i].close();
 46     oFile.close();
 47
 48     //delete the dynamically allocated arrays
 49     delete[] inFilePtr;
 50     delete[] stringPtr;
 51
 52     return 0;
 53 }

My problem is: when I compile, some error occurs with the underlined code, "error: no matching function for call to std::basic_ifstream<char>::open(std::string&)’".
can anyone explain why?
many thanks.

[Peter87]

Before C++11 there was no overload of open that takes a std::string as argument, only a C string (const char*). You can use the c_str() member function to get a C string from a std::string.
(inFilePtr[i]).open(inFileName.c_str());