C++ Programming Assignment: From Basics to Functions & Data Structures

Learning Objectives

By completing this assignment, students will be able to:

• Use variables, data types, and operators effectively in C++ programs

• Implement conditional statements and loops for program flow control

• Create and call functions with parameters and return values

• Work with arrays and vectors for storing and manipulating collections of data

• Use strings and perform basic string operations

• Read from and write to files

• Apply these concepts to solve real-world programming problems

Assignment Overview

In this assignment, you will build a Student Grade Management System that evolves from basic input/output to a more sophisticated program using functions, arrays, and file I/O. Each challenge builds on previous skills while introducing new intermediate concepts.

Real-World Context: Schools need to track student grades, calculate averages, and generate reports. Your program will help teachers manage this data efficiently.

Challenge 1: Grade Input & Basic Calculations (Beginner)

Problem Description

Create a program that allows a teacher to input grades for a single student and calculate basic statistics (average, highest, lowest).

Requirements

• Prompt the user to enter the student's name

• Ask how many grades the student has

• Use a loop to collect each grade

• Calculate and display:

  • Average grade

  • Highest grade

  • Lowest grade

• Use proper data types (string for name, float for grades)

Example Input/Output

Enter student name: Alice Johnson
How many grades does the student have? 5
Enter grade 1: 85
Enter grade 2: 92
Enter grade 3: 78
Enter grade 4: 88
Enter grade 5: 95

--- Grade Report for Alice Johnson ---
Average Grade: 87.6
Highest Grade: 95
Lowest Grade: 78

Requirements Checklist

• Use string for student name

• Use int for number of grades

• Use float for grade values

• Implement a loop to collect grades

• Calculate average, max, and min correctly

• Display results with clear formatting

Starter Code

#include <iostream>
#include <string>
using namespace std;

int main() {
    string studentName;
    int numGrades;
    float grade;
    float sum = 0;
    float highest = 0;
    float lowest = 100;
    
    // TODO: Prompt for student name
    
    // TODO: Prompt for number of grades
    
    // TODO: Loop to collect grades and calculate sum, highest, lowest
    
    // TODO: Calculate and display average, highest, lowest
    
    return 0;
}

Hints

• Use getline(cin, studentName) to read a full name with spaces

• Initialize lowest to a high value (like 100) so any grade will be lower

• Use sum / numGrades to calculate the average

• Consider using if statements inside your loop to track highest and lowest

Challenge 2: Letter Grades & Conditional Logic (Beginner)

Problem Description

Extend Challenge 1 to assign letter grades based on the calculated average.

Requirements

• Use the program from Challenge 1

• Add a function that converts a numeric grade to a letter grade:

  • A: 90-100

  • B: 80-89

  • C: 70-79

  • D: 60-69

  • F: Below 60

• Display the letter grade alongside the numeric average

• Add a pass/fail indicator (Pass if average ≥ 70, Fail otherwise)

Example Input/Output

--- Grade Report for Alice Johnson ---
Average Grade: 87.6
Letter Grade: B
Status: PASS
Highest Grade: 95
Lowest Grade: 78

Requirements Checklist

• Create a function char getLetterGrade(float average)

• Use if/else statements for grade conversion

• Display letter grade in output

• Display pass/fail status

• Handle edge cases (exactly 90, exactly 70, etc.)

Starter Code Addition

// Function to convert numeric grade to letter grade
char getLetterGrade(float average) {
    // TODO: Use if/else to return appropriate letter
    // Remember: A (90+), B (80-89), C (70-79), D (60-69), F (<60)
}

// In main(), after calculating average:
char letterGrade = getLetterGrade(average);
string status = (average >= 70) ? "PASS" : "FAIL";
cout << "Letter Grade: " << letterGrade << endl;
cout << "Status: " << status << endl;

Hints

• Use nested if/else statements or a switch statement

• The ternary operator ? : is useful for pass/fail logic

• Test your function with boundary values (90, 89, 70, 69)

Challenge 3: Multiple Students with Arrays/Vectors (Intermediate)

Problem Description

Expand the system to manage grades for multiple students. Use an array or vector to store student data.

Requirements

• Create a struct or class to hold student information (name, grades, average)

• Allow the teacher to input data for multiple students

• Store each student's data in a vector

• Calculate class statistics:

  • Class average

  • Student with highest average

  • Student with lowest average

• Display a summary report for all students

Example Input/Output

How many students? 3

--- Student 1 ---
Enter student name: Alice Johnson
How many grades? 3
Enter grade 1: 85
Enter grade 2: 92
Enter grade 3: 88

--- Student 2 ---
Enter student name: Bob Smith
How many grades? 3
Enter grade 1: 78
Enter grade 2: 82
Enter grade 3: 80

--- Student 3 ---
Enter student name: Carol White
How many grades? 3
Enter grade 1: 95
Enter grade 2: 98
Enter grade 3: 96

=== CLASS SUMMARY ===
Student Name          | Average | Letter Grade
---------------------------------------------------
Alice Johnson         |   88.3  |      B
Bob Smith             |   80.0  |      B
Carol White           |   96.3  |      A

Class Average: 88.2
Top Student: Carol White (96.3)
Bottom Student: Bob Smith (80.0)

Requirements Checklist

• Create a struct to store student data

• Use a vector to store multiple students

• Implement a function to calculate individual averages

• Implement a function to find top and bottom students

• Display formatted summary report

• Calculate and display class average

Starter Code

#include <iostream>
#include <string>
#include <vector>
#include <iomanip>
using namespace std;

struct Student {
    string name;
    vector<float> grades;
    float average;
};

float calculateAverage(vector<float> grades) {
    // TODO: Sum all grades and divide by count
}

void displayReport(vector<Student> students) {
    // TODO: Display formatted table with all students
}

int main() {
    vector<Student> students;
    int numStudents;
    
    cout << "How many students? ";
    cin >> numStudents;
    cin.ignore(); // Clear input buffer
    
    // TODO: Loop to collect student data
    // TODO: Calculate averages for each student
    // TODO: Display report
    
    return 0;
}

Hints

• Use vector<float> inside the struct to store multiple grades per student

• Use iomanip library with setw() and left for formatted table output

• The cin.ignore() function clears leftover newlines from input buffer

• Consider creating helper functions for finding min/max students

Challenge 4: File I/O & Data Persistence (Intermediate)

Problem Description

Save and load student grade data from a file so teachers can work with previously entered data.

Requirements

• Implement a function to save all student data to a file (grades.txt)

• Implement a function to load student data from a file

• Display a menu allowing teachers to:

  1. Enter new student data

  2. Load existing data from file

  3. View current data

  4. Save data to file

  5. Exit

• File format should be readable and well-organized

Example File Format (grades.txt)

Alice Johnson
3
85 92 88
Bob Smith
3
78 82 80
Carol White
3
95 98 96

Requirements Checklist

• Create void saveToFile(vector<Student> students, string filename) function

• Create vector<Student> loadFromFile(string filename) function

• Implement menu system using switch/case

• Handle file I/O errors gracefully

• Display appropriate messages for save/load operations

• Preserve data between program runs

Starter Code

#include <fstream>

void saveToFile(vector<Student> students, string filename) {
    ofstream outFile(filename);
    
    if (!outFile.is_open()) {
        cout << "Error: Could not open file for writing!" << endl;
        return;
    }
    
    // TODO: Write each student's data to file
    // Format: name on one line, number of grades, grades on next line
    
    outFile.close();
    cout << "Data saved to " << filename << endl;
}

vector<Student> loadFromFile(string filename) {
    vector<Student> students;
    ifstream inFile(filename);
    
    if (!inFile.is_open()) {
        cout << "Error: Could not open file for reading!" << endl;
        return students;
    }
    
    // TODO: Read student data from file
    // TODO: Reconstruct Student structs
    
    inFile.close();
    return students;
}

void displayMenu() {
    cout << "\n=== Grade Management System ===" << endl;
    cout << "1. Enter new student data" << endl;
    cout << "2. Load data from file" << endl;
    cout << "3. View current data" << endl;
    cout << "4. Save data to file" << endl;
    cout << "5. Exit" << endl;
    cout << "Choose option: ";
}

int main() {
    vector<Student> students;
    int choice;
    
    while (true) {
        displayMenu();
        cin >> choice;
        cin.ignore();
        
        switch(choice) {
            case 1:
                // TODO: Call function to enter new student
                break;
            case 2:
                students = loadFromFile("grades.txt");
                break;
            case 3:
                displayReport(students);
                break;
            case 4:
                saveToFile(students, "grades.txt");
                break;
            case 5:
                cout << "Goodbye!" << endl;
                return 0;
            default:
                cout << "Invalid option!" << endl;
        }
    }
}

Hints

• Use ofstream for writing and ifstream for reading

• Always check if file opened successfully with .is_open()

• Use getline(inFile, name) to read student names

• Use inFile >> grade to read numeric values

• Close files after use with .close()

Submission Guidelines

What to Submit

1. All four C++ source files (.cpp files) with your solutions

2. A grades.txt file with sample data demonstrating file I/O works

3. A README.txt file explaining:

   • How to compile and run your program

   • Any challenges you encountered

   • Features you added beyond requirements

How to Compile & Run

g++ -o gradeManager gradeManager.cpp
./gradeManager

Or in an IDE, simply build and run the project.

Submission Checklist

• All code compiles without errors

• All four challenges completed

• Program runs without crashing

• File I/O works correctly

• Output is formatted and readable

• Code includes comments explaining key sections

• README file included

Grading Rubric

Answer Key & Sample Solutions

Challenge 1: Solution

#include <iostream>
#include <string>
using namespace std;

int main() {
    string studentName;
    int numGrades;
    float grade;
    float sum = 0;
    float highest = 0;
    float lowest = 100;
    
    cout << "Enter student name: ";
    getline(cin, studentName);
    
    cout << "How many grades does the student have? ";
    cin >> numGrades;
    
    for (int i = 1; i <= numGrades; i++) {
        cout << "Enter grade " << i << ": ";
        cin >> grade;
        sum += grade;
        
        if (grade > highest) {
            highest = grade;
        }
        if (grade < lowest) {
            lowest = grade;
        }
    }
    
    float average = sum / numGrades;
    
    cout << "\n--- Grade Report for " << studentName << " ---" << endl;
    cout << "Average Grade: " << average << endl;
    cout << "Highest Grade: " << highest << endl;
    cout << "Lowest Grade: " << lowest << endl;
    
    return 0;
}

Challenge 2: Solution

#include <iostream>
#include <string>
using namespace std;

char getLetterGrade(float average) {
    if (average >= 90) {
        return 'A';
    } else if (average >= 80) {
        return 'B';
    } else if (average >= 70) {
        return 'C';
    } else if (average >= 60) {
        return 'D';
    } else {
        return 'F';
    }
}

int main() {
    string studentName;
    int numGrades;
    float grade;
    float sum = 0;
    float highest = 0;
    float lowest = 100;
    
    cout << "Enter student name: ";
    getline(cin, studentName);
    
    cout << "How many grades does the student have? ";
    cin >> numGrades;
    
    for (int i = 1; i <= numGrades; i++) {
        cout << "Enter grade " << i << ": ";
        cin >> grade;
        sum += grade;
        
        if (grade > highest) {
            highest = grade;
        }
        if (grade < lowest) {
            lowest = grade;
        }
    }
    
    float average = sum / numGrades;
    char letterGrade = getLetterGrade(average);
    string status = (average >= 70) ? "PASS" : "FAIL";
    
    cout << "\n--- Grade Report for " << studentName << " ---" << endl;
    cout << "Average Grade: " << average << endl;
    cout << "Letter Grade: " << letterGrade << endl;
    cout << "Status: " << status << endl;
    cout << "Highest Grade: " << highest << endl;
    cout << "Lowest Grade: " << lowest << endl;
    
    return 0;
}

Challenge 3: Solution

#include <iostream>
#include <string>
#include <vector>
#include <iomanip>
using namespace std;

struct Student {
    string name;
    vector<float> grades;
    float average;
};

char getLetterGrade(float average) {
    if (average >= 90) return 'A';
    else if (average >= 80) return 'B';
    else if (average >= 70) return 'C';
    else if (average >= 60) return 'D';