Problems with 2d arrays

[panagior]

Hello guys!
I have a 2d array with students and their marks! i have to calculate the averge for each student. The program compiles but the average remains 0. please help!!


public double calculateResponseAverage(String filename)
{

int col=10;
int row =8;

array = new int[row][col];


double avg=0;
for (int i=0; i<array.length; i++)
{
int sum=0;
for (int j=0; j<array[0].length; j++)
{
sum +=array[0][j];

}
avg = avg/array[0].length;
avg += sum;
}

return avg;

[jim829]

First, it is best to put your formatted code between [code][/code] tags.

public double calculateResponseAverage(String filename)  {
 
          int col=10;
          int row =8;
 
          array = new int[row][col];
 
 
              double avg=0;
              for (int i=0; i<array.length; i++)
              {
                  int sum=0;
                  for (int j=0; j<array[0].length; j++)
                  {
                      sum +=array[0][j];
 
                  }
                    avg = avg/array[0].length;
                    avg += sum;
              }
 
            return avg;     
}

I believe you need to change your row index from 0 to i.

Jim

[panagior]

Nothing happened :/ and i have another method called results...how do i call the average method in the results method so the average of each student appears next to its grades??



public void displayResults()
{


System.out.println( "Responses for" );
for(int i=0; i<=7; i++)

{

System.out.print("#" + (i+1) + " ");
for (int j = 0; j <= 9; j++)
{

System.out.print(array [i][j]);

}
System.out.println();

}

}

[jim829]

You are also using ints. To calculate averages you need to use double to preserve the decimals. And you call your first method with a filename argument which isn't used. And you dividing avg by the number of entries, not the sum.

Jim

[panagior]

ohhh...let me try that