Sorting an Array of Structs not working

OKAY...I was hoping to finish this assignment without any more help but after 4 hours of trying to find my problem I have gave in.

What I have is an Array of Structs that I need to sort, within the struct I have names stored in arrays and thats what I have to sort by, then I will have to change it to sort by the Enum within the struct as well but one thing at a time.
I just need it to sort the list first.

The prog reads information in from a file stores it in the Array of structs, prints the original list then sorts and prints the sorted list. Right now all it does it read store print original list and then prints the original list again unsorted. I cannot see where I have messed up so I am hoping a fresh set of eyes will see my error and let me know where it is and possibly what I have to do to correct it.

Code:

---

#include <string>
#include <iostream>
#include <cstring>
#include <cassert>
#include <fstream>
using namespace std;

enum year_in_school {freshman, sophomore, junior, senior, special};

struct studentrec
{
      char name[20];
      int age;
      float gpa;
      year_in_school classification;
}; //End Struct

istream &operator >>(istream &is, year_in_school &yr);
istream &operator >>(istream &is, studentrec &r);
ostream &operator <<(ostream &os, year_in_school yr);
ostream &operator <<(ostream &os, const studentrec &r);
bool operator <(studentrec st1, studentrec st2);
template <class t> void sortlist(t list[], int count);

int main(void)
{
    studentrec stlist[17];
    int i;
    int stcount;
    ifstream fin;
   
  cout << "Enter the name of the input file: ";
    string inputFileName;
    getline(cin, inputFileName);
   
    fin.open(inputFileName.data()); // Filestream Open
    assert(fin.is_open());          // Check to make sure filestream is open
 
    for (i=0; i<=17; i++)
        fin >> stlist[i];          // Filestream reads into array of structs
            if (fin.eof() );   
    fin.close();                    // Filestream Closed
 
    cout << "\n\nOriginal List of Students" << endl;  //List before Sort
        for (i=0; i<17; i++)
            cout << stlist[i];
   
    cout << "\n\nSorted List of Students" << endl;    // List after Sort
        sortlist (stlist, stcount);
       
        for (i=0; i<17; i++)
            cout << stlist[i];
   
  system ("pause");
  return 0;
}//end Main


istream &operator >>(istream &is, year_in_school &yr)
{
    int year;
 
    is >> year;

    switch( year )
    {
        case freshman:
            yr = freshman;
            break;
        case sophomore:
            yr = sophomore;
            break;       
        case junior:
            yr = junior;
            break;
        case senior:
            yr = senior;
            break;
        case special:
            yr = special;
            break;
        default:
            return (is);
            break;
    };
    return( is );
} // end Year Switch


istream &operator >>(istream &is, studentrec &r)

{
  int temp;
  char filler[80];
   
    is.get(r.name,20);
    if(is.eof())
      return is;
    is >> r.age >> r.gpa >> r.classification;
    is.getline(filler,80);
  return is;
} //end Studentrec input


ostream &operator <<(ostream &os, year_in_school yr)
{
 switch(yr)
 {
  case freshman: 
      os << "Freshman"; 
      break;
  case sophomore:
      os << "Sophomore";
      break;
  case junior:   
      os << "Junior";   
      break;
  case senior:   
      os << "Senior";   
      break;
  case special: 
      os << "Special"; 
      break;
  default:       
      os << "Unspecified" << endl;
      break;
 }
 return  os;
} //end year_in_school OS


ostream &operator <<(ostream &os, const studentrec &r)
{
    os << "          Name : " << r.name << endl;
    os << "          Age : " << r.age << endl;
    os << "          GPA : ";
    os.precision(4);
    os  << r.gpa << endl;
    os << "Classification : " << r.classification << endl;
    os << endl;

    return( os );
}  //end print function


bool operator <(studentrec st1, studentrec st2)
{
    return (strcmp(st1.name, st2.name))<0;
} //end "<" define


template <class t> void sortlist(t list[], int count)
{
  int minpos;
  int i;
  int pass;
  count--;
 
  for(pass=0; pass<count; pass++)
      {
        minpos = pass;
        for(i=pass+1; i<=count; i++) 
            if (list[i] < list[minpos])
                minpos = i;
        if(minpos != pass)
          swap(list[minpos], list[pass]);
      }
  return ;
}  // End Sortlist

---

Also here is the text file that it reads input in from called "students.txt"

Code:

---

Ericson, Josh                21        3.513        3
Sampson, Lee                45        3.7        4
Thompson, Jim                18                2.5        9
Clark, James E.              21                3.75    1
Johnson, John T.            20        1.75    0
Bradley, Bill                19                2.1    1
Fitzgerald, Thomas          20        3.6    2
Zircon, Zelda                49                2.05    5
Brown, Susan                18        2.35    0
Collin, Amanda              19        2.95    1
Weatherington, Jane          37        1.95    5
Bullington, John            23        3.516  4
Limbaugh, Rush              55        0.75    5
Cuomo, Mario                71        2.98    5
Ford, John                  17        0.00    0
Bush, Maynard                18        2.65    1
Maynard, Jill                22        3.15    3

---

Also DEV-C++ will not recognize the "system("pause");" command now...Last night before I added the sort it was working fine would read store print and stop, now it just compiles, executes and exits the prog,all I see is the prog window flash up on the screen...I tried commenting out all the sort stuff to see if that was it but not no matter what it exits and never pauses...Any ideas on that...Other progs that I have with the pause command work fine...it will stop on those but not this one.

Thanks in advance everyone.

Trace the stcount variable. You will find that you forgot to initialise it.

Code:

---

studentrec stlist[17];
   
...

for (i=0; i<=17; i++)
    fin >> stlist[i];

---

That should be < 17 and not <= 17.

Guys thanx for the debug...I must have stared at that code for more than 4 hours this morning...I never saw those mistakes...I corrected and it worked fine...Now the problem is that he wants us to sort the array of structs by the year_in_school classification.

I changed this

Code:

---

bool operator <(studentrec st1, studentrec st2)
{
    return (strcmp(st1.name, st2.name))<0;
} //end "<" define

---

to this

Code:

---

bool operator <(studentrec st1, studentrec st2)
{
    return (strcmp(st1.classification, st2.classification))<0;
} //end "<" define

---

and I get this error
In function `bool operator<(studentrec, studentrec)':
154 cannot convert `year_in_school' to `const char*' for argument `1' to `int strcmp(const char*, const char*)'

I dont understand the error and my teacher is not availible...What does the strcmp return so that the sort will work I guess is what is causing the error...I think it wants me to use a static cast to convert the Year_in_school to an int ...But I thought that ENUMs were ints...So I dont understand the error...

In this case, you are comparing integral types. Do not use strcmp, instead just do a simple:
return st1.classification < st2.classification;

Oh OK...So since I am comparing two ENUMs and they are represented by INTs I dont have to compare them simply see which is larger/smaller whatever than the other...OK...why didnt it just say that...

Well I ran it and it almost worked...It sorted the list according to classification except for 2 of the records....

Code:

---

Zircon, Zelda                49                2.05    5   
Limbaugh, Rush              55        0.75    5

---

were the first two names in the sorted list...Then it went down the list just like it should..
What confuses me is that not only are both of them "Unspecified" but there are more than these two that are represented by a "5" in the classification input range...Any ideas???

What's your latest code?

>> for(i=pass+1; i<=count; i++)
Did you fix his problem where you should be using < instead of <=. Note that it also means that pass < count in your outer loop needs to be adjusted, too.

My latest code is this

Code:

---

#include <string>
#include <iostream>
#include <cstring>
#include <cassert>
#include <fstream>
using namespace std;

enum year_in_school {freshman, sophomore, junior, senior, special};

struct studentrec
{
      char name[20];
      int age;
      float gpa;
      year_in_school classification;
}; //End Struct

istream &operator >>(istream &is, year_in_school &yr);
istream &operator >>(istream &is, studentrec &r);
ostream &operator <<(ostream &os, year_in_school yr);
ostream &operator <<(ostream &os, const studentrec &r);
bool operator <(studentrec st1, studentrec st2);
template <class t> void sortlist(t list[], int count);

int main(void)
{
    studentrec stlist[17];
    int i;
    int stcount = 0;
    ifstream fin;
   
  cout << "\n\nEnter the name of the input file: ";
    string inputFileName;
    getline(cin, inputFileName);
   
    fin.open(inputFileName.data()); // Filestream Open
    assert(fin.is_open());          // Check to make sure filestream is open
 
    for (i=0; i<17; i++)
        fin >> stlist[i], stcount++;          // Filestream reads into array of structs
            if (fin.eof() );   
    fin.close();                    // Filestream Closed
 
    cout << "\n\n********Original List of Students********\n" << endl;  //List before Sort
        for (i=0; i<17; i++)
            cout << stlist[i];
   
    cout << "\n\n\n\n********Sorted List of Students********\n" << endl;    // List after Sort
        sortlist (stlist, stcount);
       
        for (i=0; i<17; i++)
            cout << stlist[i];
   
  system ("pause");
  return 0;
}//end Main


istream &operator >>(istream &is, year_in_school &yr)
{
    int year;
 
    is >> year;

    switch( year )
    {
        case 0:
            yr = freshman;
            break;
        case 1:
            yr = sophomore;
            break;       
        case 2:
            yr = junior;
            break;
        case 3:
            yr = senior;
            break;
        case 4:
            yr = special;
            break;
        default:
            return (is);
            break;
    };
    return( is );
} // end Year Switch


istream &operator >>(istream &is, studentrec &r)

{
  int temp;
  char filler[80];
   
    is.get(r.name,20);
    if(is.eof())
      return is;
    is >> r.age >> r.gpa >> r.classification;
    is.getline(filler,80);
  return is;
} //end Studentrec input


ostream &operator <<(ostream &os, year_in_school yr)
{
 switch(yr)
 {
  case freshman: 
      os << "Freshman"; 
      break;
  case sophomore:
      os << "Sophomore";
      break;
  case junior:   
      os << "Junior";   
      break;
  case senior:   
      os << "Senior";   
      break;
  case special: 
      os << "Special"; 
      break;
  default:       
      os << "Unspecified" << endl;
      break;
 }
 return  os;
} //end year_in_school OS


ostream &operator <<(ostream &os, const studentrec &r)
{
    os << "          Name : " << r.name << endl;
    os << "          Age : " << r.age << endl;
    os << "          GPA : ";
    os.precision(3);
    os  << r.gpa << endl;
    os << "Classification : " << r.classification << endl;
    os << endl;

    return( os );
}  //end print function


bool operator <(studentrec st1, studentrec st2)
{
    return st1.classification < st2.classification;
} //end "<" define


template <class t> void sortlist(t list[], int count)
{
  int minpos;
  int i;
  int pass;
  count--;
 
  for(pass=0; pass<count; pass++)
      {
        minpos = pass;
        for(i=pass; i<count; i++) 
            if (list[i] < list[minpos])
                minpos = i;
        if(minpos != pass)
          swap(list[minpos], list[pass]);
      }
  return ;
}  // End Sortlist

---

The sorted list comes out like this

Code:

---

********Sorted List of Students********

        Name : Zircon, Zelda     
          Age : 49
          GPA : 2.05
Classification : Unspecified


          Name : Limbaugh, Rush   
          Age : 55
          GPA : 0.75
Classification : Unspecified


          Name : Johnson, John T. 
          Age : 20
          GPA : 1.75
Classification : Freshman

          Name : Brown, Susan     
          Age : 18
          GPA : 2.35
Classification : Freshman

          Name : Ford, John       
          Age : 17
          GPA : 0
Classification : Freshman

          Name : Bradley, Bill     
          Age : 19
          GPA : 2.1
Classification : Sophomore

          Name : Clark, James E.   
          Age : 21
          GPA : 3.75
Classification : Sophomore

          Name : Collin, Amanda   
          Age : 19
          GPA : 2.95
Classification : Sophomore

          Name : Bush, Maynard     
          Age : 18
          GPA : 2.65
Classification : Sophomore

          Name : Fitzgerald, Thomas
          Age : 20
          GPA : 3.6
Classification : Junior

          Name : Ericson, Josh     
          Age : 21
          GPA : 3.51
Classification : Senior

          Name : Bullington, John 
          Age : 23
          GPA : 3.52
Classification : Special

          Name : Sampson, Lee     
          Age : 45
          GPA : 3.7
Classification : Special

          Name : Cuomo, Mario     
          Age : 71
          GPA : 2.98
Classification : Unspecified


          Name : Weatherington, Jane
          Age : 37
          GPA : 1.95
Classification : Unspecified


          Name : Thompson, Jim     
          Age : 18
          GPA : 2.5
Classification : Unspecified


          Name : Maynard, Jill     
          Age : 22
          GPA : 3.15
Classification : Senior

---

OK I took out the "count--" in the sort function and that made it run one more time and corrected the
Maynard, Jill
at the end so now all I have is the first two records not in place..I still cant find that problem

I didn't see the count-- in your original code. That code was actually probably ok. Sorry about that. I don't see what the actual issue is right now.