Question

I have a problem with getting the min,max, and average of an elements of 2D array.

I have a 2D array which contains Students and Grades.

I am generating the grades with rand. For example When I enter 2,2 it prints me out

Courses : 01   02   Average   Min   Max
    ID   
    01     8   50     29
    02    74   59     29

, My average function takes the first ones average and doesnt take the others average.

Here is my code ;

int A[30][30];

int findAverage(int noOfStudents ,int noOfGrades ){

    float sum,average;




    for (int i = 0 ; i < noOfGrades ; i++) {
        for (int j = 0; j<noOfStudents; j++) {

        sum += A[i][j];

        }
        average = sum / noOfGrades;
       // cout << "   " << format(average);
        sum = 0;
        return format(average);

    }

and here how I use it

int main() {

    int noOfCourses , noOfStudents;
    cin >> noOfCourses >> noOfStudents;
    cout << "Courses : " ;

    for (int i = 0; i < noOfCourses; i++) {
        if (i+1 >= 10) {

            cout << i+1 << "   ";
        }else{
            cout <<"0" << i+1 << "   ";

        }
    }

    cout << "Average   Min   Max";

    for(int i=0; i<noOfStudents; i++) {         //This loops on the rows.        

        for(int j=0; j<noOfCourses; j++) {     //This loops on the columns
            A[i][j] = genGrade(); 
        }
    }

    cout << "\n    ID   " << endl;

    for(int i=0; i<noOfStudents; i++) {  //This loops on the rows.

        if (i+1 >= 10) {

            cout <<"    " << i+1 << "   ";
        }else{
            cout <<"    0" << i+1 << "   ";

        }

        //cout <<"    0" << i+1 << "   ";

        for(int j=0; j<noOfCourses; j++) {  //This loops on the columns


            if (A[i][j] >= 10 && A[i][j] <=99) {

                cout <<" " << A[i][j]  << "  ";
            }
            if(A[i][j] < 10) {

                cout <<"  " << A[i][j] << "  ";
            }
            if (A[i][j] == 100) {

                cout << A[i][j] << "  ";
            }
        }
        cout <<"   "<<findAverage(noOfStudents,noOfCourses);
        cout << endl;
    }
}

What am I doing wrong ? Also How could I get the min,max of the per array?

Answer 1

The problem is that in your findAverage function you have a return statement within the loop that is looping through the rows. If you want a very simple fix add another parameter to the findAverage function that indicates which row to calculate the average for.

int findAverage(int course ,int noOfGrades ){

    float sum,average;


    for (int j = 0; j<noOfStudents; j++) {

        sum += A[course][j];

    }
    average = sum / noOfGrades;
    return format(average);
 }

and call it like this

cout <<"   "<<findAverage(i,noOfCourses);