Student Marking Calculator

Question

This is a student module marks calculator that I was asked to write for a uni revision session in year 2.

Is this a good example of modern C++ code? Is there anything I can improve on or need to change to become a better programmer?

#include <iostream>
#include <cstdlib>

float student_results[5][2];

unsigned int input_student_result(unsigned int);

float input_student_weighting(unsigned int);

unsigned int input_exam_result();

float calculate_exam_weighting();

float calculate_module_mark();

int main() {

    // Coursework 1

    for (unsigned int i = 0; i < 4; ++i) {

        student_results[i][0] = input_student_result(i);

        student_results[i][1] = input_student_weighting(i);

    }

    student_results[4][0] = input_exam_result();

    student_results[4][1] = calculate_exam_weighting();

    std::cout << "Module mark = " << calculate_module_mark() << '\n';
    std::cout << '\n';

    system("pause");

    return 0;

}

unsigned int input_student_result(unsigned int n) {

    unsigned int input_validation = 0;

    do {

        std::cout << "Enter coursework " << (n + 1) << " result <0 - 100> = ";
        std::cin >> input_validation;

    } while (!(input_validation >= 1 && input_validation <= 100));

    return input_validation;

}

float input_student_weighting(unsigned int n) {

    float input_validation = 0;

    do {

        std::cout << "Enter coursework " << (n + 1) << " weighting 0.1 or 0.2 = ";
        std::cin >> input_validation;

    } while (!(input_validation == 0.1f || input_validation == 0.2f));

    return input_validation;

}

unsigned int input_exam_result() {

    unsigned int input_validation = 0;

    do {

        std::cout << "Enter exam result <0-100> = ";
        std::cin >> input_validation;

    } while (!(input_validation >= 1 && input_validation <= 100));

    return input_validation;

}

float calculate_exam_weighting() {

    float exam_weighting = (1 - (student_results[0][1] + student_results[1][1] + student_results[2][1] + student_results[3][1]));

    std::cout << "Exam weighting = " << exam_weighting << '\n';

    return exam_weighting;

}

float calculate_module_mark() {

    float module_mark{
            (student_results[0][0] * student_results[0][1]) +
            (student_results[1][0] * student_results[1][1]) +
            (student_results[2][0] * student_results[2][1]) +
            (student_results[3][0] * student_results[3][1]) +
            (student_results[4][0] * student_results[4][1])
    };

    return module_mark;

}

Answer 1

Here is how you can improve your code:

• Define a class instead of using an array for unrelated numbers (0 to 100 vs. 0.1 or 0.2)
• Use a std::vector instead of a fixed size array
• Prefer double over float, since it has higher precision
• Prefer integer arithmetic over floating point arithmetic, since it won't lead to strange results that easily
• Group your global functions into a class, to express that they belong together
• Add error checking for all calls to std::cin >> var

By the way, you don't look like a beginner since you

• don't import the complete std namespace
• use \n instead of std::endl

This is already quite good.