C++ File Loop Problems

[pianokey09]

    cout << "Enter Student ID (999 to end): ";  cin >> searchId;
        inFile.open(file + ".txt");
        inFile.ignore(80, '\n');
        while (searchId != 999)
        {
            for (int i = 0; i <= count; i++)
            {
                inFile >> ID >> lastName >> firstName >> q1 >> q2 >> q3 >> q4 >> final;
                if (searchId == ID)
                {
                    avgGrd(q1, q2, q3, q4, final, average, grade);
                    cout << "  " << left << setw(12) << lastName << "  " << setw(12) << firstName << ' ' 
                        << setw(3) << average << ' ' << setw(2) << grade << endl;
                    cout << "Enter Student ID (999 to end): ";  cin >> searchId;
                }
            }
        }cout << "Enter any character: ";  cin >> end;

This is what I have so far. And this works up to about 3 iterations and then stops. I'm not sure why. Also, everytime I try to make it so it will output "Record not found!" for an invalid input it does that for every input thereafter. Please Help!

[Ancient Dragon]

line 2: how is variable file declared? If it is std::string, you can't do it that way.

file += ".txt" 
infile.open(file.c_str())

if file is declared as a character array do this:

strcat(file,".txt");
infile.open(file);

Your program doesn't need that for next loop. Just a while loop will do ok

while(true)
{
    cout << "Enter Student ID (999 to end): ";  
        cin >> searchId;
    if( searchId == 999 )
       break;
    while( inFile >> ID >> lastName >> firstName >> q1 >> q2 >> q3 >> q4 >> final )
    {
       // do something with the data
      if (searchId == ID)
      {
          avgGrd(q1, q2, q3, q4, final, average, grade);
          cout << "  " << left << setw(12) << lastName << "  " << setw(12) << firstName << ' ' 
             << setw(3) << average << ' ' << setw(2) << grade << endl;
          break;
      }
  }
 }

[pianokey09]

#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>

using namespace std;
// Function prototypes
void avgGrd(int, int, int, int, int, double&, string&);
int findLow(int, int, int, int);
int findHigh(int, int, int, int);
int qfAvg(double, int, double&);

void main()
{
    // Variable declarations
    ifstream inFile;
    string lastName, firstName, grade, file;
    char end;
    int ID, q1, q2, q3, q4, final, count = 0, searchId;
    double sum1 = 0, sum2 = 0, sum3 = 0, sum4 = 0, sumFinal = 0, sumAvg = 0;
    int q1Count = 0, q2Count = 0, q3Count = 0, q4Count = 0, finalCount = 0, avgCount = 0;
    double avg;
    double average;


    cout << "Enter file name: "; cin >> file;
    inFile.open(file + ".txt");
    if (!inFile.fail())
    {
        cout << fixed << setprecision(1);
        cout << endl << setw(53) << "Fall 2012 Student Grade Report:" << endl << endl;
        cout << "No.    ID   Last Name    First Name  Quiz1 Quiz2 Quiz3 Quiz4 Final  Avg   Grd" << endl;
        cout << "------------------------------------------------------------------------------" << endl;
        inFile.ignore(80, '\n');
        inFile >> ID;
        while (!inFile.eof())
        {

            count++;
            inFile >> lastName >> firstName >> q1 >> q2 >> q3 >> q4 >> final;
            sum1 += q1; sum2 += q2; sum3 += q3; sum4 += q4; sumFinal += final; 
            avgGrd(q1, q2, q3, q4, final, average, grade);
            sumAvg += average;
            cout << right << setw(3) << count << " " << setw(6) << ID << "  " << left 
                << setw(12) << lastName << " " << left << setw(12) << firstName << " ";
                if (q1 > 0)
                {
                    cout <<right << setw(3) << q1;
                    q1Count++;
                }
                else
                    cout << "   ";
                if (q2 > 0)
                {
                    cout << right << setw(6) << q2;
                    q2Count++;
                }
                else
                    cout << "      ";
                if (q3 > 0)
                {
                    cout << right << setw(6) << q3;
                    q3Count++;
                }
                else
                    cout << "      ";
                if (q4 > 0)
                {
                    cout << right << setw(6) << q4;
                    q4Count++;
                }
                else
                    cout << "      ";
            cout << right << setw(5) << final << right << setw(8) << average << "   " << left << setw(7) << grade << endl;
            inFile >> ID;
        }
        inFile.close();
        cout << "                                      ----------------------------------------" << endl;
        cout << "                                       ";
        qfAvg(sum1, q1Count, avg);
        cout << setw(6) << avg;
        qfAvg(sum2, q2Count, avg);
        cout << setw(6) << avg; 
        qfAvg(sum3, q3Count, avg);
        cout << setw(6) << avg;
        qfAvg(sum4, q4Count, avg);
        cout << setw(6) << avg;
        qfAvg(sumFinal, count, avg);
        cout << setw(5) << avg;
        qfAvg(sumAvg, count, avg);
        cout << setw(5) << avg << endl;

        cout << "Enter Student ID (999 to end): ";  cin >> searchId;
        inFile.open(file + ".txt");
        inFile.ignore(80, '\n');
        while (searchId != 999)
        {
            for (int i = 0; i <= count; i++)
            {
                inFile >> ID >> lastName >> firstName >> q1 >> q2 >> q3 >> q4 >> final;
                if (searchId == ID)
                {
                    avgGrd(q1, q2, q3, q4, final, average, grade);
                    cout << "  " << left << setw(12) << lastName << "  " << setw(12) << firstName << ' ' 
                        << setw(3) << average << ' ' << setw(2) << grade << endl;   
                    cout << "Enter Student ID (999 to end): ";  cin >> searchId;      
                }
            }cout << "Record not found!" << endl;
        }cout << "Enter any character: ";  cin >> end;
    }
    else
        cout << endl << "File Open Failed!" << endl;
}

// Function definitions
void avgGrd(int q1, int q2, int q3, int q4, int final, double& average, string& grade)
{   
    int low = findLow(q1, q2, q3, q4);
    int high = findHigh(q1, q2, q3, q4);
    average = ((q1 + q2 + q3 + q4 + final + final) - low + high) / 6.;
    if (average >= 96.66)
        grade = "A+";
    else if (average >= 93.33)
        grade = 'A';
    else if (average >= 90)
        grade = "A-";
    else if (average >= 86.66)
        grade = "B+";
    else if (average >= 83.33)
        grade = 'B';
    else if (average >= 80)
        grade = "B-";
    else if (average >= 76.66)
        grade = "C+";
    else if (average >= 73.33)
        grade = 'C';
    else if (average >= 70)
        grade = "C-";
    else if (average >= 66.66)
        grade = "D+";
    else if (average >= 63.33)
        grade = 'D';
    else if (average >= 60)
        grade = "D-";
    else
        grade = 'F';

}
int findLow(int q1, int q2, int q3, int q4)
{
    int low = q1;
    if (q2 < low)
        low = q2;
    if (q3 < low)
        low = q3;
    if (q4 < low)
        low = q4;
    return low;
}
int findHigh(int q1, int q2, int q3, int q4)
{
    int high = q1;
    if (q2 > high)
        high = q2;
    if (q3 > high)
        high = q3;
    if (q4 > high)
        high = q4;
    return high;
}
int qfAvg(double sum, int Count, double& avg)
{
    avg = sum / Count;
    return avg;
}

This is the whole code. The entire thing works. Even inputting 999. The only problem I am having is I have to have it cout << "Record not found!" << endl; when the input is not valid. How I have it right here it does it but then I am stuck in an infinite loop of "Record not found!". I don't know how to fix this.

[Ancient Dragon]

The entire thing works.

Not possible. Line 27 is wrong, as I explained in my last post. open() doesn't take a std::string as the first argument, it takes only char*.

and line 28 should be if( !infile.is_open()) instead of if( infile.fail())

[pianokey09]

I'm not sure what you are saying is not possible. The program runs. Perfectly actually. I just can't make the last part output properly.

[Ancient Dragon]

I gave you the code the read the file, you just chose to ignore it.

[pianokey09]

What I'm saying is I don't understand what you mean. The file reads. Reading the file is not the issue

[Tumlee]

Not possible. Line 27 is wrong, as I explained in my last post. open() doesn't take a std::string as the first argument, it takes only char*.

Perhaps he's using some old or otherwise nonstandard compiler that's somehow automatically typecasting std::string to const char*?

[pianokey09]

I'm not sure but I am using Microsoft Visual Studios 2010 and it compiles and reads the file without a problem. I just can't get the second part of the program to work properly.

[nullptr]

Not possible. Line 27 is wrong, as I explained in my last post. open() doesn't take a std::string as the first argument, it takes only char*.

This was discussed in this thread. and is possible, though I can't vouch for every compiler accepting a std::string as the file name.

This entire section of code is quite a mess.

cout << "Enter Student ID (999 to end): "; 
cin >> searchId;
inFile.open(file + ".txt");
inFile.ignore(80, '\n');
while (searchId != 999)
{
    for (int i = 0; i <= count; i++)
    {
        inFile >> ID >> lastName >> firstName >> q1 >> q2 >> q3 >> q4 >> final;
        if (searchId == ID)
        {
            avgGrd(q1, q2, q3, q4, final, average, grade);
            cout << " " << left << setw(12) << lastName << " " << setw(12) << firstName << ' '
            << setw(3) << average << ' ' << setw(2) << grade << endl;
            cout << "Enter Student ID (999 to end): "; cin >> searchId;
        }
    }cout << "Record not found!" << endl;
}cout << "Enter any character: "; 

cin >> end;

What constitutes a valid Student ID?
cin >> searchId;
Validate that searchId falls within the acceptable range.

If (searchId == 999) 
    return 0;

Also change void main() to int main()

inFile.open(file + ".txt");
check that you actually opened the file and handle if unsuccessful

Get rid of the following loops.
while (searchId != 999) and for (int i = 0; i <= count; i++)

Use something like:

bool bFound = false;
while (inFile >> ID >> lastName >> firstName >> q1 >> q2 >> q3 >> q4 >> final)
{
    if (searchId == ID)
    {
       bFound = true;
       // do other stuff
    }
}

if (!bFound)
{
    // error ID not found
    // handle error
}

[pianokey09]

A valid search ID is one that is found within the file. SO you would have to search the entire file to find out. I can actually open the file and handle it successfully. There is a first half to this outputs perfectly fine. The biggest prblem I'm having is that I have to be able to search for the ID's and I can't because it will only allow me to go through the file once and I don't know how to change that. SO I can search for the ID's as long as they are in sequential order and if I skip ahead I can't go back and I don't know how to fix that. I need to be able to search the entire file every time.

[Ancient Dragon]

after going through the file you have to reset the file stream back to the beginning of the file.

infile.feekp(0);