Gradebook Program - Small Problem, Need Assistance

CaitlynCraft · #1 13-Nov-2007, 18:02

Hi everyone, I am going to post a gradebook program I wrote recently, but am having some trouble with. I need to have averages in both the Columns and Rows, but can't seem to get the Columns to work, right now it just shows the same as the Rows...If anyone can see my error, which I am sure is there, please let me know, and thanks.

CPP / C++ / C Code:

#include <stdio.h>
#include <stdlib.h>

#define MAX_ROWS 3
#define MAX_COLS 3


void getData      (int   table[][MAX_COLS]); 
void rowAverage   (int   table[][MAX_COLS],
                   float rowAvrg []);
void colAverage   (int   table[][MAX_COLS],
                   float colAvrg []);
void  printTables (int   table[][MAX_COLS], 
                   float rowAvrg[], 
                   float colAvrg[],
                   FILE *fout);

int main (void)
{

	int   table  [MAX_ROWS][MAX_COLS];

   FILE *fout;
   
   fout = fopen ("studentGrades.dat", "w");

	float rowAve [MAX_ROWS] = {0.0};
	float colAve [MAX_COLS] = {0.0};


	getData (table);
	rowAverage (table, rowAve);
    colAverage (table, colAve);

	printf("\n");
	printTables (table, rowAve, colAve, fout);
    printf("Open up \'studentGrades.dat\' to see the grades...\n");
    system ( "PAUSE" ) ;
    return 0;
}
void getData (int table[][MAX_COLS]) 
{
     int row;
     int col;

	
    for (row = 0.0; row < MAX_ROWS; row++)
	   for (col = 0.0; col < MAX_COLS; col++)
	       {
	        printf("\nEnter a grade for student %d and grade %d: ", row+1, col+1);
	        scanf("%d", &table[row][col]);
	       }
	return;
}

void rowAverage (int    table[][MAX_COLS],
                 float  rowAvrg [])
{
         int row;
         int col;
          
	for (row = 0.0; row < MAX_ROWS; row++)
	    {
	     for (col = 0.0; col < MAX_COLS; col++)
	         rowAvrg[row] += table [row][col];
	     rowAvrg [row] /=  MAX_COLS;
	    }
	return;
}

void colAverage (int   table[][MAX_COLS],
                   float colAvrg [])
{
    int row;
    int col;
    
    for (col = 0.0; col < MAX_COLS; col++)
    {
        for (row = 0.0; row < MAX_ROWS; row++)
        {
            colAvrg[col] += table [col][row];
        }
        colAvrg [col] /= MAX_ROWS;
    }
    return;                      
}
void printTables (int    table[][MAX_COLS],
                  float  rowAvrg[], 
                  float  colAvrg[],
                  FILE *fout)
{
          int row;
          int col;

    
    for (col = 1; col <= MAX_COLS; col = col + 1)
    {
        fprintf(fout, "  Exm%d"  , col);   
    }
    
        fprintf(fout, "\n"); 
    
    
	for (row = 0.0; row < MAX_ROWS; row++)
	   {
        fprintf (fout, "Stu%d ", row+1);
	    for (col = 0.0; col < MAX_COLS; col++)
	    fprintf (fout,"%4d", table[row][col]);
	    fprintf (fout,"   | %4.2f\n", rowAvrg [row]);
	   }

fprintf (fout,"-------------------------------------------------\n");
fprintf (fout,"     ");

	    for (col = 0.0; col < MAX_COLS; col++)
	    fprintf (fout,"%6.2f", colAvrg [col]);
	    
	return;
}

TurboPT · #2 13-Nov-2007, 20:43

Merely change this line in the colAverage() function:

CPP / C++ / C Code:

            colAvrg[col] += table [col][row];

To this:

CPP / C++ / C Code:

            colAvrg[col] += table [row][col];

Output

Code:

  Exm1  Exm2  Exm3
Stu1   40  50  60   | 50.00
Stu2   55  65  75   | 65.00
Stu3   85  95 100   | 93.33
-------------------------------------------------
      60.00 70.00 78.33

Also, where you have declared 'row' and 'col' as integers, there is no need to initialize them with 0.0 -- just 0 is ok.
There were warnings for all those:

Code:

... : warning C4244: '=' : conversion from 'const double' to 'int', possible loss of data

CaitlynCraft · #3 13-Nov-2007, 20:47

I can't thank you enough! That worked! Smiles!

Howard_L · #4 13-Nov-2007, 23:01

Also be aware that down a couple of lines below what TurboPT referred to you have:

CPP / C++ / C Code:

         colAvrg [col] /= MAX_ROWS;

...which is not noticed in output because table[MAX_ROWS][MAX_COLS] is 3x3.
But if you were to change that size in the future????

Do yourself a favor in the future and place some strategic printf()'s to check your values like:

CPP / C++ / C Code:

    /* in main() */
    colAverage (table, colAve);
    for(i = 0; i < MAX_COLS; i++)
    {
       printf("colAve[%d]= %f  ", i, colAve[i] );
    }
    /* and this down in colAverage()... */
    for (col = 0.0; col < MAX_COLS; col++)
    {
        printf("colAvrg");
        for (row = 0.0; row < MAX_ROWS; row++)
        {
            colAvrg[col] += table [row][col];
            printf("[%d]= %3.3f,  ",col, colAvrg[col]);
        }
        colAvrg [col] /= MAX_COLS;
        printf(" colAvrg[%d]= %3.3f \n", col, colAvrg [col] );
    }

They will show EXACTLY what is going on.
It takes a little time but reduces facial squinch lines in the long run...

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Rate This Thread
Rate This Thread:

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Two-Tier data dissemination code installation problem	nidhibansal1984	Computer Software Forum - Linux	6	16-Sep-2007 10:13
Problem compiling MFC program	shvalb	MS Visual C++ / MFC Forum	1	21-Sep-2006 20:14
Pipeline freeze simulation	darklightred	C++ Forum	6	27-Jul-2006 19:37
Fresh Small C++ Program :P	Sabin044	C++ Forum	40	02-Feb-2006 18:57
Small help with this program please	NigelZen	C Programming Language	3	28-Aug-2005 23:17

Gradebook Program - Small Problem, Need Assistance

Re: Gradebook Program - Small Problem, Need Assistance

Re: Gradebook Program - Small Problem, Need Assistance

Re: Gradebook Program - Small Problem, Need Assistance