Introduction to Programming in C

📘 Arrays (1D, 2D) and Basic Operations in C

Arrays in C are used to store multiple values of the same type in a single variable. They are essential for organizing large sets of data efficiently and are widely used in all types of programming tasks — from simple iteration to complex data processing.

🔹 What is an Array?

An array is a collection of elements of the same data type placed in contiguous memory locations and accessed using an index.

int marks[5];

This declares an integer array of 5 elements: marks[0] to marks[4].

🧮 Initializing Arrays

• int nums[5] = {1, 2, 3, 4, 5};
• float prices[] = {99.5, 75.0, 60.5}; ← Compiler determines size
• char vowels[5] = {'a', 'e', 'i', 'o', 'u'};

🔁 Accessing Array Elements

int nums[3] = {10, 20, 30};
printf("%d", nums[1]); // Output: 20

📊 Looping Through Arrays

You can iterate through arrays using loops:

int i, arr[5] = {10, 20, 30, 40, 50};
for(i = 0; i < 5; i++) {
    printf("%d\n", arr[i]);
}

📂 Common Operations on 1D Arrays

• Find the maximum or minimum value
• Calculate the sum or average
• Reverse the array
• Search for a particular element
• Sort the array (Bubble Sort, Selection Sort, etc.)

📘 Example: Sum of Array Elements

int arr[5] = {1, 2, 3, 4, 5}, sum = 0;
for(int i = 0; i < 5; i++) {
    sum += arr[i];
}
printf("Total = %d", sum);

📦 Two-Dimensional Arrays (2D Arrays)

Useful for representing matrices, grids, and tables.

int matrix[2][3] = {
    {1, 2, 3},
    {4, 5, 6}
};

🔄 Looping Through 2D Arrays

for(int i = 0; i < 2; i++) {
    for(int j = 0; j < 3; j++) {
        printf("%d ", matrix[i][j]);
    }
    printf("\n");
}

📚 Real-Life Example (UdaanPath)

Assume you store marks of 3 students in 5 subjects for UdaanPath's scholarship assessment:

int marks[3][5]; // 3 students, 5 subjects each

📝 Practice Tasks

1. Input 10 numbers and print them in reverse order.
2. Find the largest number in an array.
3. Accept a 2x2 matrix and print its transpose.
4. Search for an element in an array and display its index.
5. Write a program to sort elements of an array in ascending order.

📌 Summary

• Arrays allow storing multiple values of the same type.
• Use 1D arrays for lists and 2D arrays for tables or matrices.
• Looping and indexing are the keys to working with arrays effectively.

✅ Coming Next

In the next chapter, we’ll explore Strings in C — how to store, manipulate, and use character arrays using string handling functions.