Hi my college class was given a group assignment to read a multi-line text file, drop the lowest score, then average the score from the remaining numbers. I've run into a problem when prompted for the filename of the text file. Although I type it in correctly, it won't load. I have the file in the same folder that the program is located. Please help:
#include<iostream>
#include<fstream>
#include<string>
using namespace std;
const int NROWS =10;
const int NCOLS =10;
void theProgram();
//Function loads immediately upon opening the program and describes the purpose of the program
//and its functionality.
int ReadTxtFile(ifstream &file, string name[], double test[][NCOLS], int ncolUsed=3);
//Function reads data from a tab delimited file, whose first column is a string and the others are
//double or int. The function returns the number of rows read. The requires three parameters to be
//passed to it. The fourth parameter is has a default value of 3.
void outPutData(string header, string name[], double test[][NCOLS], int nDataPts, int ncolUsed=3);
//The function prints out the data read from the file. The function requires four parameters to be
//passed to it. Does not return any value.
int main(){
string name[NROWS];
string header, filename;
double test[NROWS][NCOLS];
char next;
int nDataRows;
ifstream file; //Declares file as an input file stream
theProgram(); //Invokes the function that displays the program information
cout<<"Please give me the filenames containing the test scores\n";
getline(cin,filename);
//Opens the file and checks if the file has opened correctly
file.open(filename);
if(file.fail()){
cout<<"Failed to open input file "<<filename<<endl;
exit(1);
}
getline(file,header);// Reads the column headers as a string
nDataRows=ReadTxtFile(file, name, test); // Calls the function to read the file
file.close();
cout<< "Number of records in the file is "<<nDataRows<<endl;
outPutData(header,name, test, nDataRows); //Calls the function to output the data read from the file
cin>>next;
} //End of main
void theProgram(){
cout<<"************************************************************************\n";
cout<<"* ******************************************************************** *\n";
cout<<"* *This program will help the faculty to analyze the test scores and * *\n";
cout<<"* *assign grades. It reads a tab delimited file that contains the * *\n";
cout<<"* *raw score for different tests and drops the lowest score. It then * *\n";
cout<<"* *calcluates the average percentage of the remaining test scores. * *\n";
cout<<"* *Based on the average, the program then assigns a letter grade. * *\n";
cout<<"* ******************************************************************** *\n";
cout<<"************************************************************************\n";
}
void outPutData( string header, string name[], double test[][NCOLS], int nDataRows, int ncolUsed)
{
cout<<"\t"<<header<<endl;
for(int i=0; i<nDataRows; i++){
cout<<i<<"\t"<<name[i]<<"\t";
for(int j=0; j<ncolUsed; j++){
cout<<test[i][j]<<"\t";
}
cout<<endl;
}
char next;
cin>>next;
}
int ReadTxtFile(ifstream &file, string name[], double test[][NCOLS], int ncolUsed)
{
int i=0;
char next;
while (!file.eof()) //repeat until end of file
{
file>>name[i];
for(int j=0; j<ncolUsed; j++){
file>>test[i][j];
}
file.get(next);
if(!file.eof()){
file.putback(next);
}
i++;
}
return(i-1);
}
Before C++11, file.open() accepts a char*, which is C-string containing the name of the file to be opened , however, filename is of string type, you need to do the following:
file.open(filename.c_str());
in order to read from the file.
EDIT: thanks to Benjamin Lindley, you can pass string to open() in C++11. You may need to check the exe file generated from your code can access your file, they may not be in same directory.