C++ - For loop not running properly

Todd88 · 04-04-2008, 12:12 PM

We have project that reads a file that a user inputs and then fills an array from the inputted file and then prints out the array. I am having trouble getting this all to work with a struct, array, and for loop. It is printing two random numbers at the end and I'm not sure why. Here is the program:

Code:

// This program takes an array from a file and allows the user to manipulate
// the data in the file.

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

using namespace std;

struct studentType
    {
        string Name;
        int ID;
        int score;
        };

int main()
{ 
    int counter;
    ifstream inFile;
    string inputFile;
    
    studentType studentList[40];
    
    cout << "Enter the name of the input file: ";
    cin >> inputFile;
    
    inFile.open(inputFile.c_str());
    
    if(!inFile)
    {
         cout << "Invalid file name" << endl;
         system("pause");
         return 1;
         }

    inFile >> studentList[0].Name >> studentList[0].ID >> studentList[0].score;

    for (counter = 1; inFile; counter++)
    {
         inFile >> studentList[counter].Name
                >> studentList[counter].ID
                >> studentList[counter].score;
         cout << studentList[counter].Name <<  " ";
         cout << studentList[counter].ID << " ";
         cout << studentList[counter].score << " " << endl;
            }
    
     inFile.close();
     
     system("pause");
}

The file that is inputted is here:

Code:

Alex 		1220	62	
Betsy		1121	70	
Candace		2221	83	
Don 		3324	90	
Earl		4678	51	
Francesca	5555	86	
Guiles		6666	83	
Henrietta	7777	73	
Ignacius	8888	63	
Joliet		9999	81	
Kris		1010	66	
Lenny		1111	76	
Mark		1221	50	
Noah		1331	92	
Oscar		1441	73
Prince		1442	75
Queenie		7778	73
Rob		2222	83

Taquito · 04-24-2008, 12:03 AM

you're not reading from file.

you should use fread ( http://www.cplusplus.com/reference/c...dio/fread.html )

i think this should work for you:

while(!feof(f))
fread(&studentList,sizeof(studentType),20,f);

where f is the stream to your file.

04-24-2008, 12:03 AM	#2 (permalink)
Taquito Registered User Join Date: Apr 2008 Posts: 1 OS: xp	Re: C++ - For loop not running properly you're not reading from file. you should use fread ( http://www.cplusplus.com/reference/c...dio/fread.html ) i think this should work for you: while(!feof(f)) fread(&studentList,sizeof(studentType),20,f); where f is the stream to your file.