Question

Read the function definitions of the two functions: “compute_st_ave” and “compute_quiz_ave”.

Write a function that calculates the average of student averages. (Student averages are stored in st_ave [5] array). Include a statement to print this average on the screen.

Declare this function above the “main” function where other functions are declared.

In the main program, invoke this function.

//Reads quiz scores for each student into the two-dimensional array grade //(but the input code is not shown in this display). Computes the average //score for each student and the average score for each quiz. Displays //the quiz scores and the averages.

#include “stdafx.h”

#include <iostream>

#include <iomanip>

const int NUMBER_STUDENTS = 5, NUMBER_QUIZZES = 3;

void compute_st_ave(const int grade[][NUMBER_QUIZZES], double st_ave[]);

//Precondition: Global constants NUMBER_STUDENTS and NUMBER_QUIZZES

//are the dimensions of the array grade. Each of the indexed variables

//grade[st_num-1, quiz_num-1] contains the score for student st_num on //quiz quiz_num.

//Postcondition: Each st_ave[st_num-1] contains the average for student

//number stu_num.

void compute_quiz_ave(const int grade[][NUMBER_QUIZZES], double quiz_ave[]);

//Precondition: Global constants NUMBER_STUDENTS and NUMBER_QUIZZES

//are the dimensions of the array grade. Each of the indexed variables

//grade[st_num-1, quiz_num-1] contains the score for student st_num on //quiz quiz_num.

//Postcondition: Each quiz_ave[quiz_num-1] contains the average for quiz //number quiz_num.

void display(const int grade[][NUMBER_QUIZZES], const double st_ave[], const double quiz_ave[]);

//Precondition: Global constants NUMBER_STUDENTS and NUMBER_QUIZZES are //the dimensions of the array grade. Each of the indexed variables //grade[st_num-1, quiz_num-1] contains the score for student st_num on //quiz quiz_num. Each st_ave[st_num-1] contains the average for student //stu_num. Each quiz_ave[quiz_num -1] contains the average for quiz //number quiz_num.

//Postcondition: All the data in grade, st_ave, and quiz_ave has been //output.

int main( )

{

    using namespace std;

    int grade[NUMBER_STUDENTS][NUMBER_QUIZZES];

    double st_ave[NUMBER_STUDENTS];

    double quiz_ave[NUMBER_QUIZZES];

//The code for filling the array grade goes here.

    for (int st_num = 1; st_num <= NUMBER_STUDENTS; st_num++)

    {

        for (int quiz_num = 1; quiz_num <= NUMBER_QUIZZES; quiz_num++)

            {cout << “Enter the grade [” << st_num <<”][“<<quiz_num<< “]              

            =”;

            cin >> grade[st_num -1][quiz_num -1];

            }   

    }

    compute_st_ave(grade, st_ave);

    compute_quiz_ave(grade, quiz_ave);

    display(grade, st_ave, quiz_ave);

    system (“pause”);

    return 0;

}

void compute_st_ave(const int grade[][NUMBER_QUIZZES], double st_ave[])

{

    for (int st_num = 1; st_num <= NUMBER_STUDENTS; st_num++)

    {//Process one st_num:

        double sum = 0;

        for (int quiz_num = 1; quiz_num <= NUMBER_QUIZZES; quiz_num++)

            sum = sum + grade[st_num -1][quiz_num -1];

        //sum contains the sum of the quiz scores for student number       

        //st_num.

        st_ave[st_num -1] = sum/NUMBER_QUIZZES;

        //Average for student st_num is the value of st_ave[st_num-1]

    }

}

void compute_quiz_ave(const int grade[][NUMBER_QUIZZES], double quiz_ave[])

{

    for (int quiz_num = 1; quiz_num <= NUMBER_QUIZZES; quiz_num++)

   {//Process one quiz (for all students):

        double sum = 0;

        for (int st_num = 1; st_num <= NUMBER_STUDENTS; st_num++)

            sum = sum + grade[st_num -1][quiz_num -1];

        //sum contains the sum of all student scores on quiz number

        //quiz_num.

        quiz_ave[quiz_num -1] = sum/NUMBER_STUDENTS;

        //Average for quiz quiz_num is the value of quiz_ave[quiz_num-1]

    }

}

//Uses iostream and iomanip:

void display(const int grade[][NUMBER_QUIZZES],

                        const double st_ave[], const double quiz_ave[])

{

    using namespace std;

    cout.setf(ios::fixed);

    cout.setf(ios::showpoint);

    cout.precision(1);

    cout << setw(10) << "Student"

         << setw(5) << "Ave"

         << setw(15) << "Quizzes\n";

    for (int st_num = 1; st_num <= NUMBER_STUDENTS; st_num++)

    {//Display for one st_num:

        cout << setw(10) << st_num

             << setw(5) << st_ave[st_num-1] << " ";

        for (int quiz_num = 1; quiz_num <= NUMBER_QUIZZES; quiz_num++)

            cout << setw(5) << grade[st_num -1][quiz_num -1];

        cout << endl;

    }

    cout << "Quiz averages = ";

    for (int quiz_num = 1; quiz_num <= NUMBER_QUIZZES; quiz_num++)

        cout << setw(5) << quiz_ave[quiz_num -1];

    cout << endl;

}

Answer 1

//main.cpp

#include <iostream>
#include <iomanip>
const int NUMBER_STUDENTS = 4, NUMBER_QUIZZES = 3;

void compute_st_ave(const int grade[][NUMBER_QUIZZES], double st_ave[]);

void compute_quiz_ave(const int grade[][NUMBER_QUIZZES], double quiz_ave[]);

void display(const int grade[][NUMBER_QUIZZES],
const double st_ave[], const double quiz_ave[]);

int main( )
{
using namespace std;
int grade[NUMBER_STUDENTS][NUMBER_QUIZZES];
double st_ave[NUMBER_STUDENTS];
double quiz_ave[NUMBER_QUIZZES];

//The code for filling the array grade goes here, but is not shown.
compute_st_ave(grade, st_ave);
compute_quiz_ave(grade, quiz_ave);
display(grade, st_ave, quiz_ave);
return 0;
}

void compute_st_ave(const int grade[][NUMBER_QUIZZES], double st_ave[])
{
for (int st_num = 1; st_num <= NUMBER_STUDENTS; st_num++)
{//Process one st_num:
double sum = 0;
for (int quiz_num = 1; quiz_num <= NUMBER_QUIZZES; quiz_num++)
sum = sum + grade[st_num -1][quiz_num -1];
//sum contains the sum of the quiz scores for student number st_num.
st_ave[st_num -1] = sum/NUMBER_QUIZZES;
//Average for student st_num is the value of st_ave[st_num-1]
}
}

void compute_quiz_ave(const int grade[][NUMBER_QUIZZES], double quiz_ave[])
{
for (int quiz_num = 1; quiz_num <= NUMBER_QUIZZES; quiz_num++)
{//Process one quiz (for all students):
double sum = 0;
for (int st_num = 1; st_num <= NUMBER_STUDENTS; st_num++)
sum = sum + grade[st_num -1][quiz_num -1];
//sum contains the sum of all student scores on quiz number quiz_num.
quiz_ave[quiz_num -1] = sum/NUMBER_STUDENTS;
//Average for quiz quiz_num is the value of quiz_ave[quiz_num-1]
}
}

//Uses iostream and iomanip:
void display(const int grade[][NUMBER_QUIZZES],
const double st_ave[], const double quiz_ave[])
{
using namespace std;
cout.setf(ios::fixed);
cout.setf(ios::showpoint);
cout.precision(1);
cout << setw(10) << "Student"
<< setw(5) << "Ave"
<< setw(15) << "Quizzes\n";
for (int st_num = 1; st_num <= NUMBER_STUDENTS; st_num++)
{//Display for one st_num:
cout << setw(10) << st_num
<< setw(5) << st_ave[st_num-1] << " ";
for (int quiz_num = 1; quiz_num <= NUMBER_QUIZZES; quiz_num++)
cout << setw(5) << grade[st_num -1][quiz_num -1];
cout << endl;
}

cout << "Quiz averages = ";
for (int quiz_num = 1; quiz_num <= NUMBER_QUIZZES; quiz_num++)
cout << setw(5) << quiz_ave[quiz_num -1];
cout << endl;
}

=====================================================================

sample output: