Multi dimensional array

average.cpp

#include <stdio.h>
int main()
{
    int Marks[3][5] = {
        {71, 75, 67, 73, 45}, // maths
        {77, 65, 56, 78, 58}, // physics
        {63, 57, 79, 88, 33}  // chemistry
    };

    int out_index;
    int in_index;
    int overall_sum = 0;

    for (out_index = 0; out_index < 3; out_index++)
    {
        for (in_index = 0; in_index < 5; in_index++)
        {
            overall_sum += Marks[out_index][in_index];
        }
    }

    float overall_avg = float(overall_sum) / float(out_index * in_index);

    printf("Overall average marks %.2f", overall_avg);

    return 0;
}

sum_even.cpp

#include <stdio.h>
int main()
{
    int Marks[3][5] = {
        {71, 75, 67, 73, 45}, // maths
        {77, 65, 56, 78, 58}, // physics
        {63, 57, 79, 88, 33}  // chemistry
    };

    int out_index;
    int in_index;
    int sum_of_even_marks = 0;

    for (out_index = 0; out_index < 3; out_index++)
    {
        for (in_index = 0; in_index < 5; in_index++)
        {
            if (Marks[out_index][in_index] % 2 == 0)
            {
                sum_of_even_marks += Marks[out_index][in_index];
            }
        }
    }

    printf("The sum of even numbers is %d", sum_of_even_marks);

    return 0;
}

sum_loop.cpp

#include <stdio.h>
int main()
{
    int Marks[3][5] = {
        {71, 75, 67, 73, 45}, // maths
        {77, 65, 56, 78, 58}, // physics
        {63, 57, 79, 88, 33}  // chemistry
    };

    printf("First Marks %d\nLast marks %d", Marks[0][0], Marks[2][4]);

    // a. Average marks in Physics
    int p_index;
    int p_sum = 0;

    for (p_index = 0; p_index < 5; p_index++)
    {
        p_sum = p_sum + Marks[1][p_index];
    }

    float p_avg = float(p_sum) / float(p_index);
    printf("Average marks for Physics is %.2f", p_avg); // physics

    // b. Average marks in maths
    int m_index;
    int m_sum = 0;
    while (m_index < 5)
    {
        m_sum = m_sum + Marks[0][m_index];
        m_index++;
    }

    float m_avg = float(m_sum) / float(m_index);
    printf("\nAverage marks for Maths is %.2f", m_avg); // maths

    // c. Average marks in Chemistry
    int c_index;
    int c_sum = 0;

    do
    {
        c_sum = c_sum + Marks[2][c_index];
        c_index++;
    } while (c_index < 5);

    float c_avg = float(c_sum) / float(c_index);
    printf("\nAverage marks for Chemistry is %.2f", c_avg); // chemistry

    return 0;
}