selection sort records of chars

Hello
The book I am using is not of help, so I would love if someone could give me a few hints.

I have already declared three 2D arrays of lname, fname, and grades and have written a function to read the input file "scores.txt" into the arrays and returned the length.

The problem I am having is working on a void function to sort records of students by last name. I have to use sort selection and sort the names in ascending order by last name. The last name, first name, and grades are all 2D arrays, which I have declared as lname, fname, and grades. The list below is an example of what I need to sort. It includes the last name, first name, and 5 grades.

Code:

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Smith Tom 25 25 20 15 24
Broom Linda 22 23 25 25 20
Tanner Joe 22 15 24 18 20

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This is what I have so far

Code:

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#include <fstream>
#include <iostream>
#include <cstdlib>
#include <cstring>


using namespace std;

const char LNAME_SIZE = 20;
const char FNAME_SIZE = 15;
const char GRADES_SIZE = 20;

const char STUDENTS = 32;


int readScores(ifstream& fin, char lname[][LNAME_SIZE + 1],
                            char fname[][FNAME_SIZE + 1], char grades[][GRADES_SIZE + 1]);
        // reads scores.txt into the arrays and returns the length

void sortRecords(char lname[][LNAME_SIZE + 1], int length);
        // sorts the records by last name in ascending order




void main(void)
{
        ifstream fin;
        ofstream fout;

        char lname[STUDENTS][LNAME_SIZE + 1];
        char fname[STUDENTS][FNAME_SIZE + 1];
        char grades[STUDENTS][GRADES_SIZE + 1];
        int length;


        // connect the input stream to the file scores.txt
        fin.open("scores.txt");
       
        // tests the input stream
        if ( fin.fail() )
        {
                cerr << "Error opening file scores.txt for reading.  Aborting!"
                        << endl
                        << endl;
                exit(1);
        }


        // read the file into the arrays
        length = readScores(fin, lname, fname, grades);

        // sorts the records in alphabetical order by last name
        sortRecords(lname, length);


        // connect the output stream to the file records.txt
        fout.open("records.txt");
       
        // tests the output stream
        if ( fout.fail() )
        {
                cerr << "Error opening file records.txt for reading.  Aborting!"
                        << endl
                        << endl;
                exit(1);
        }


        fin.close();
        fout.close();


}// end main()



int readScores(ifstream& fin, char lname[][LNAME_SIZE + 1],
                            char fname[][FNAME_SIZE + 1], char grades[][GRADES_SIZE + 1])
{
        int length = 0;
       

        fin.getline(lname[length], LNAME_SIZE + 1, ' ');
        while ( !fin.eof() )
        {
                fin.getline(fname[length], FNAME_SIZE + 1, ' ');
                fin.getline(grades[length], GRADES_SIZE + 1, ' ');
                length++;
                fin.getline(lname[length], LNAME_SIZE + 1, ' ');
        }// end while


        cout << length << endl << endl;
        for (int i = 0; i < length; i++)
        {
                cout << lname[i] << " ";
                cout << fname[i] << " ";
                cout << grades[i] << " ";
        }

        cout << endl << endl;


        return(length);
}// end readScores()





void sortRecords(char lname[][LNAME_SIZE + 1], int length)
{
        int minPos;

        // finds minimum position
        for (int i = 0; i < length; i++) {
                if (lname[i] < lname[minPos]) {
                minPos = i;
                }
        }


}// end sortRecords()

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I have no clue what to do next for the sortRecords. Like I said, my book is of no help. If someone could please help, it would be greatly appreciated.

i looked at your code and it seems to me that u have
the function prototypes in 2 places

and your main() cant both take void and get void

it should get an int instead

Quote:

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i looked at your code and it seems to me that u have
the function prototypes in 2 places

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Where? I don't see the prototypes in two places.

Quote:

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and your main() cant both take void and get void

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Yes, it can.

I think you should look into a sorting algorithm like bubblesort, or quick sort or something. Just do a search on google.

I did a search on google and it didn't help. As for the bubble sort or quick sort, I haven't been over those in my class. All we have done is a linear search and a selection sort, and we have to use a selection sort. All my teachers examples of selection sort have used integers, not characters, but he wants us to sort characters out. Thanks for the help though. If anyone else can give me a hint or help of any kind, I would appreciate it. Thanks in advance.

it should take an int because the functions are returning int's

Quote:

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it should take an int because the functions are returning int's

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No, it should be taking an int because that's standard. What you said was that it can't (not shouldn't) take an int. I simply corrected you.

If you need to sort chars, cast int on them and compare as if they were int.

Assuming the first character of the last name is uppercase, (if not, use toupper in ctype.h) do the following. (or something similar)

Code:

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if ((int) lname[i][0] < (int) lname[ii][0])
{
        switch(); //Do whatever action nessicary;
}

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I'm not sure of the way selection sort works.. but I think you get the idea.

i meant in that code!

I hope that you get helped from our friends Above ....

believe me ... the best way to do it ... is to get a new book...
that will do the first step...
and I hope you do the same thing that I am doing ....
2 hours everyday .... on this GREAT web site...
Read and Read and Read other problems.....

:rolleyes: You Got it now :rolleyes:

try to make a class of :
name
Array[ number of grads]
then make an array of this class
it is easier this way....

:)