Expert: vijayan - 11/19/2010

Question
Hello, i have a program here that is almost finished. But i
am in need to implement an array or vector for processing.

- "3.   The program must utilize one array or vector for
processing – not just output.  I would suggest reading the
assignment scores into an array."

that is the last requirement of the program that i need to
put in but i have no idea how to.


#include <iostream>
#include <stdlib.h>
#include <fstream>

//Student Name-Aris Lara
using namespace std;
int f_assignmentavg (int a, int b, int c, int d)
{
 int aavg;
 aavg=(a+b+c+d)/4;
 return (aavg);
}

int f_testassigmentavg (int a, int b, int c)
{
   int tstavg;
   tstavg = (a+b+c) /3;
   return (tstavg);
}
int f_checkpassfail (int att, int testavg)
{    bool pass = true;
    if (att < 30)
      {pass = false; cout << "failed [attendance]" ;  }
      else
       if (testavg <60)
         {pass = false ; cout << "failed [grades] "  ;}
    return (pass);
}
    
int main(int argc, char *argv[])
{
 string lastname, name, phone, pref;

 int test1, test2, count = 0;

 int a1, a2, a3 , a4;

 int attendance;


 int assignment_avg, test_assignment_avg;

 ifstream myfile ("grades.txt");
 if (myfile.is_open())
 {
while (! myfile.eof() )
//while (count < 4)
{ //count +=1;
   {
  
  // while( myfile >> line ) {
     myfile >> name;
     cout << "First Name: " << name << endl; //}
   
     myfile >> lastname;
     cout << "Last Name: " << lastname << endl;
 
     myfile >> test1;
     cout << "Test 1: " << test1  << endl;   

     myfile >> test2 ;
     cout << "Test 2: " << test2 << endl;

     myfile >> a1 ;
     cout << "Assigment 1: " << a1 <<endl;
        
     myfile >> a2 ;
     cout << "Assigment 2: " << a2 <<endl;
        
     myfile >> a3 ;
     cout << "Assigment 3: " << a3 <<endl;
        
     myfile >> a4 ;
     cout << "Assigment 4: " << a4 <<endl;
        
     myfile >> attendance ;
     cout << "Attendance: " << attendance << endl;
    
      // replace this code with function
     //assignment_avg = (a1 + a2 + a3 + a4 ) / 4   ;
     //cout << "Assignment Average : " << assignment_avg <<
endl ;
     assignment_avg = f_assignmentavg(a1,a2,a3,a4);
      
      //replace this code with function
     //test_assignment_avg = ( assignment_avg + test1 +
test2 ) / 3 ;
     test_assignment_avg = f_testassigmentavg
(assignment_avg, test1 , test2 );
     cout << "Average : " << test_assignment_avg << endl;
    
  //home work output
     cout << endl << endl << "--- Assignment output ----"
<< endl;
     cout << name << " " << lastname << endl;         
                  
 if (f_checkpassfail  (attendance, test_assignment_avg) )
             cout << "[pass good grades & Attendance] ";
                           
     if (test_assignment_avg > 90) cout << "A" << endl;
       else
        if (test_assignment_avg >80) cout << "B" << endl;
          else
            if (test_assignment_avg > 70 ) cout << "C"
<<endl ;   
            else
            if (test_assignment_avg >60) cout << "D" <<endl
;
            else
            if (test_assignment_avg <50) cout << "F" <<endl
;
     cout << endl;
     
     cout << "---------------------------------------------
---------------------- " << endl;
     
   }
   
 }
 myfile.close();
}

 else cout << "Unable to open file";

 system("PAUSE");        
 return 0;
}

Answer
> " I would suggest reading the assignment scores into an array"

Since the number of assignments (four) is a constant known at compile time, an array would do.

a. Define an array for reading the assignment scores.
replace
   int a1, a2, a3 , a4;

with
   
   enum { NUM_ASSIGNMENTS = 4 } ;
   int a[NUM_ASSIGNMENTS] ;


b. Read the scores into the array

Instead of

    myfile >> a1 ;
    cout << "Assigment 1: " << a1 <<endl;
       
    // a2, a3, a4 etc

Write a loop to read the assignment values into the array:

    for( int i=0 ; i<NUM_ASSIGNMENTS ; ++i )
    {
         myfile >> a[i] ;
         cout << "Assigment " << i << ": " << a[i] <<endl;
    }

c. Use a[0], a[1], a[2], a[3] instead of a1, a2, a3, a4 in the rest of the program.