C++ (CP 123) LAB 5 SOLVED INTERACTIVE

LAB WORK 4: PRACTICE LOOP, SELECTION, and ARRAY (if any) Ngunguto, a high school student with a keen interest in programming, found himself inspired during a computer science class project. His teacher challenged the students to create a tool that could help with academic performance tracking. Motivated by this challenge, Ngunguto decided to develop a program that would calculate and display the average scores and corresponding grades for five of his classmates based on their performance in four subjects: Mathematics, Science, English, and History.

To begin, Ngunguto gathered the scores of his classmates, ensuring he had accurate data for each subject. He structured the data in a clear format, creating a list that included the names of the students and their respective scores. This organization was crucial, as it would allow him to efficiently process the information later. Next, Ngunguto set about writing the program. He started by defining a function that would calculate the average score for each student. To make the program user- friendly, he included comments to explain each part of the code. He implemented a grading scale that would categorize the average scores: an A for scores between 90 and 100, a B for 80 to 89, a C for 70 to 79, a D for 60 to 69, and an F for scores below 60.

After coding the logic, Ngunguto ran several tests with sample data to ensure the program worked correctly. He was thrilled to see that it not only calculated the averages accurately but also determined the correct grades for each student. To enhance the output, he formatted the results to display each student’s name, average score, and corresponding grade neatly.

Encouraged by his success, Ngunguto decided to present his project to the class. During his presentation, he explained the process he followed, the challenges he faced, and how he overcame them. His classmates were impressed with the program’s functionality, and many expressed interests in using it for their own academic tracking.

This project not only solidified Ngunguto’s programming skills but also fostered a sense of collaboration among his peers. They discussed potential improvements, such as adding features for tracking progress over time or incorporating a graphical user interface. Inspired by the feedback, Ngunguto felt motivated to continue enhancing the program, turning it into a valuable tool for academic success. Through this experience, he learned the importance of data management, problem-solving, and the power of technology in education.

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Solution Implementation

Write a complete C++ program that solves the problem using functions.

Solution Code (Click to show)

#include <iostream>
#include <string>
using namespace std;
 
// Function prototypes
double CalAvg(int total, int numSubjects);
string GradeScore(double average, string &performance);
string DispGrade(char grade, string performance);
int SumScore(int math, int physics, int chemistry, int generalStudies);
 
int main() {
    // Variables to store subject scores
    int math, physics, chemistry, generalStudies;
    
    cout << "=== JAMAL'S ACADEMIC PERFORMANCE ANALYSIS ===" << endl;
    cout << "Enter Jamal's scores (0-100) for each subject:" << endl;
    
    // Input with validation
    cout << "Mathematics: ";
    cin >> math;
    while (math < 0 || math > 100) {
        cout << "Invalid score! Enter Mathematics score (0-100): ";
        cin >> math;
    }
    
    cout << "Physics: ";
    cin >> physics;
    while (physics < 0 || physics > 100) {
        cout << "Invalid score! Enter Physics score (0-100): ";
        cin >> physics;
    }
    
    cout << "Chemistry: ";
    cin >> chemistry;
    while (chemistry < 0 || chemistry > 100) {
        cout << "Invalid score! Enter Chemistry score (0-100): ";
        cin >> chemistry;
    }
    
    cout << "General Studies: ";
    cin >> generalStudies;
    while (generalStudies < 0 || generalStudies > 100) {
        cout << "Invalid score! Enter General Studies score (0-100): ";
        cin >> generalStudies;
    }
    
    // Calculate total score
    int total = SumScore(math, physics, chemistry, generalStudies);
    
    // Calculate average score
    double average = CalAvg(total, 4);
    
    // Determine grade and performance
    string performance;
    char grade = GradeScore(average, performance);
    
    // Display grade and get final message
    string finalMessage = DispGrade(grade, performance);
    
    // Performance summary
    cout << "\n=== PERFORMANCE SUMMARY ===" << endl;
    cout << "Total Score: " << total << "/400" << endl;
    cout << "Average Score: " << average << endl;
    cout << "Final Grade: " << grade << endl;
    cout << "Performance: " << performance << endl;
    cout << finalMessage << endl;
    
    return 0;
}
 
// Function to calculate total score
int SumScore(int math, int physics, int chemistry, int generalStudies) {
    int total = math + physics + chemistry + generalStudies;
    return total;
}
 
// Function to calculate average score
double CalAvg(int total, int numSubjects) {
    return static_cast<double>(total) / numSubjects;
}
 
// Function to determine grade and performance
string GradeScore(double average, string &performance) {
    char grade;
    
    if (average >= 90) {
        grade = 'A';
        performance = "Excellent";
    } else if (average >= 80) {
        grade = 'B';
        performance = "Good";
    } else if (average >= 70) {
        grade = 'C';
        performance = "Average";
    } else if (average >= 60) {
        grade = 'D';
        performance = "Below Average";
    } else {
        grade = 'F';
        performance = "Poor";
    }
    
    return grade;
}
 
// Function to display grade and return welcome message
string DispGrade(char grade, string performance) {
    cout << "\n=== GRADE REPORT ===" << endl;
    cout << "Grade: " << grade << endl;
    cout << "Performance Level: " << performance << endl;
    
    return "Warmly Welcome Again!";
}

Explain the purpose of the SumScore function and how it interacts with CalAvg.

Answer (Click to show)

The SumScore function:

• Calculates total score by adding all four subject scores
• Returns integer value representing the sum of all scores
• Called from main function with individual subject scores as parameters

Interaction with CalAvg:

• SumScore does not directly call CalAvg in this implementation
• The main function calls CalAvg using the total returned by SumScore
• This creates a logical workflow: Sum → Average → Grade
• Separation of concerns - each function has a single responsibility

How does the GradeScore function determine both grade and performance description?

Answer (Click to show)

The GradeScore function uses:

string GradeScore(double average, string &performance) {
    char grade;
    
    if (average >= 90) {
        grade = 'A';
        performance = "Excellent";
    } else if (average >= 80) {
        grade = 'B';
        performance = "Good";
    } // ... continues for other grades

Key features:

• Reference parameter &performance to return performance description
• Return value is the letter grade as char
• Comprehensive grading scale covering all performance levels
• Clear mapping between numeric averages and qualitative descriptions

What is the role of the DispGrade function and how does it return the final message?

Answer (Click to show)

The DispGrade function:

string DispGrade(char grade, string performance) {
    cout << "\n=== GRADE REPORT ===" << endl;
    cout << "Grade: " << grade << endl;
    cout << "Performance Level: " << performance << endl;
    
    return "Warmly Welcome Again!";
}

Its roles are:

1. Display grade information to the user
2. Show performance level description
3. Return farewell message as a string
4. Separate display logic from calculation logic

Sample Output:

View Expected Output (Click to show)

=== JAMAL'S ACADEMIC PERFORMANCE ANALYSIS ===
Enter Jamal's scores (0-100) for each subject:
Mathematics: 85
Physics: 92
Chemistry: 78
General Studies: 88

=== GRADE REPORT ===
Grade: B
Performance Level: Good

=== PERFORMANCE SUMMARY ===
Total Score: 343/400
Average Score: 85.75
Final Grade: B
Performance: Good
Warmly Welcome Again!

Key C++ Function Concepts Demonstrated:

C++ Function Concepts (Click to show)

This lab demonstrates these C++ function concepts:

1. Function Declaration - using prototypes at the top
2. Function Definition - implementing each function’s logic
3. Parameter Passing - by value and by reference
4. Return Values - different return types (int, double, char, string)
5. Function Calls - calling functions from main and other functions
6. Input Validation - while loops for score validation
7. Modular Programming - separating concerns into different functions
8. Program Organization - logical flow between functions

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