Appendix E: Projects & Practice

Table of Contents

• Table of Contents
• E.1 Mini Projects
• E.2 Practice Challenges
• E.3 Exercises
• E.4 Solutions

E.1 Mini Projects

• Calculator: Build a simple calculator supporting +, -, *, / operations.
• Student Database: Create a program to store and search student records.
• File Copier: Write a program to copy contents from one file to another.

E.2 Practice Challenges

1. Reverse the words in a sentence.
2. Count the frequency of each character in a string.
3. Implement a basic stack using arrays.

E.3 Exercises

1. Write a program to check if a number is prime.
2. Implement a function to sort an array of integers.
3. Write a program to find the largest element in a 2D array.

E.4 Solutions

E.4.1 Solution 1

int is_prime(int n) {
    if (n < 2) return 0;
    for (int i = 2; i * i <= n; i++)
        if (n % i == 0) return 0;
    return 1;
}

E.4.2 Solution 2

void sort(int arr[], int n) {
    for (int i = 0; i < n-1; i++)
        for (int j = 0; j < n-i-1; j++)
            if (arr[j] > arr[j+1]) {
                int t = arr[j]; arr[j] = arr[j+1]; arr[j+1] = t;
            }
}

E.4.3 Solution 3

int max2D(int arr[][N], int rows, int cols) {
    int max = arr[0][0];
    for (int i = 0; i < rows; i++)
        for (int j = 0; j < cols; j++)
            if (arr[i][j] > max) max = arr[i][j];
    return max;
}