C++ File I/O creating the input file by user help!

[suhdominic]

#include <iostream>
#include <fstream>
 
using namespace std;
 
int main()
{
    cout  << fixed  << showpoint;
 
    float a0,a1,a2,a3,a4,a5,a6,a7,a8;   // Nine constant values in the polynomial
    float x;            // Value for x in the polynomial
    float Polynomial;   // Value for the polynomial
    ifstream inData;    // declares input stream
    ofstream outData;   // declares output stream
    string fileName;    // Inputs file name
 
    cout << "This program computes and outputs the result of the polynomial" << endl;
    cout << "The values for a8,a7,a6,a5,a4,a3,a2,a1,a0 and x are read from " << endl;
    cout << "inputfile.dat and the outputs are written to outputfile.dat" << endl;
 
    cout << "Enter the input file name: ";      // Prompt
    cin >> fileName;    // Inputs the file name
    inData.open(fileName.c_str());      // Opens the input file with the name
 
    outData.open("outputfile.dat");
    // binds program variable outData to the output file "outputfile.dat"
 
    // Inputs values of a and x for the polynomial function
    inData  >> a8 >> a7 >> a6 >> a5 >> a4 >> a3 >> a2 >> a1 >> a0 >> x;
 
    // The function of the polynomial and it calculates the result of the function
    Polynomial = (a8*pow(x, 8)) + (a7*pow(x, 7)) + (a6*pow(x, 6)) + (a5*pow(x, 5))
               + (a4*pow(x, 4)) + (a3*pow(x, 3)) + (a2*pow(x, 2)) + (a1*x) + a0;
outData  << Polynomial  << endl; // Prints the result of the polynomial
 
    return 0;
}

this program i made it to ask me to type the name of the inputfile that will be created but it is not created i typed inputfile.dat but it is not there what is wrong with it help!

[Ganon11]

Well, you shouldn't be creating an input file at all - a new input file would be empty, so no data could be given to the program. Make sure inputfile.dat is already made in the same folder as the program, and fill it with the polynomial coefficients and the x value.