Thread: Would this formula give me The GPA of a list of numbers

Average = gArray[x] + 1 / j - 1;

the j is in a do while loop and every time I enter a GPA in it increments if that helps

I'll post the code if you guys need it you might want to take a look at what I have so far

Yeah it stands for Grade Point Average I would like to take a list of numbers being a array and add them all up then divide by how many numbers are in the array just not sure how to go about it here is what I have even though its wrong

Code:

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

int main()
{
  int x;  
  const int MAX = 30;
  char choice = ' ';
  float gArray[MAX];
  float Average;
  int j = 1;
  
  do 
  {
      printf("\nEnter a GPA: ");
      scanf("%f",&gArray);
      
      printf("\nDo you wish to calculate current GPA: (y) YES (n) NO?) ");
      scanf(" %c", &choice);  
  
      if (choice == 'y')
        for(x = 0; x <= j; x++)
        {
           Average = gArray[x] + 1 / j - 1;
           break;
        } 
        
      j++; 
   }while (choice == 'n');
   
   for (x = 0; x <= j - 1; x++)
   { 
       printf("\n%f1",gArray[x]);
   }    
  
  printf("\nAverage = %f\n",Average);
  printf("%d",j);
  system("PAUSE");	
  return 0;
}

say I had

3.5
2.8
3.0
2.5
4.0
3.7
----

19.5

average = score1 + score2 + score 3 + score4 + score5 + score6 / 6;

this would work for 6 scores but what if I had more or less?

say I had

3.5
2.8
3.0
2.5
4.0
3.7
----

19.5

average = score1 + score2 + score 3 + score4 + score5 + score6 / 6;

this would work for 6 scores but what if I had more or less?

I thought the j++ does that is there a better way

No. I have no idea where on earth you got that formula. Can you get your money back?

Keep a sum that increments with every added grade. Divide by the number of grades you have. Don't use integer division.

Code:

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

int main()
{
  int x; 
  int gradeCount = 0;
  int MAX = 30;
  float gArray[MAX];
  float sum;
  float avg;
  char choice = ' ';
  
  do
  {
      printf("\nEnter GPA: ");
      scanf("%f", &gArray);
      
      gradeCount++;
      
      printf("\nCalculate GPA:(Yes or No)? ");
      scanf(" %c", &choice);
  }while ( choice == 'n');
  
    for ( x = 0; x <=MAX-(MAX - gradeCount); x++)
    {
      sum += gArray[x];
      avg = sum / MAX-(MAX - gradeCount);  
    }
   
   printf("\nAverage = %f\n",avg);   
   system("PAUSE");	
   return 0;
}

I put in this list of numbers and I get this answer the answer isn't correct I don't know if its My calculations or something else I hope someone can help me figure this out heres my test data




Enter GPA: 3.5

Calculate GPAYes or No)? n

Enter GPA: 2.8

Calculate GPAYes or No)? n

Enter GPA: 3.0

Calculate GPAYes or No)? n

Enter GPA: 2.5

Calculate GPAYes or No)? n

Enter GPA: 4.0

Calculate GPAYes or No)? n

Enter GPA: 3.7

Calculate GPAYes or No)? y

Average = 12196996456264528000000000000000.000000
Press any key to continue . . .

Enter GPA: 3.5

Calculate GPAYes or No)? n

Enter GPA: 2.8

Calculate GPAYes or No)? n

Enter GPA: 3.0

Calculate GPAYes or No)? n

Enter GPA: 2.5

Calculate GPAYes or No)? n

Enter GPA: 4.0

Calculate GPAYes or No)? n

Enter GPA: 3.7

Calculate GPAYes or No)? y
gArray[0] = 3.700000
gArray[1] = 0.000000
gArray[2] = 0.000000
gArray[3] = 0.000000
gArray[4] = 0.000000
gArray[5] = 177016798723160610000000000000000.000000
Press any key to continue . . .



Well, it appears that my data is way off I just don't know why its doing that

here's my code again

Code:

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

int main()
{
  int x; 
  int gradeCount = 0;
  int MAX = 30;
  float gArray[MAX];
  float sum = 0;
  float avg;
  char choice = ' ';
  
  do
  {
      printf("\nEnter GPA: ");
      scanf("%f", &gArray);
      
      gradeCount++;
      
      printf("\nCalculate GPA:(Yes or No)? ");
      scanf(" %c", &choice);
  }while ( choice == 'n');
  
    for ( x = 0; x < gradeCount; ++x)
    {
      printf("gArray[%d] = %f\n",x,gArray[x]);  
    }
   
   //printf("\nAverage = %f\n",avg);   
   system("PAUSE");	
   return 0;
}

P.S. I don't know how to turn on a wall flag on my compiler too advanced for me

Code:

scanf("%f", &gArray);

You aren't referencing a slot in the array.. you are just entering in each GPA into the first slot of the array.