C - Arrays

Overview

An array stores a fixed-size sequence of elements of the same type in contiguous memory.

Learning Objectives

• Declare, initialize, and index arrays.
• Understand array bounds and decay to pointer.

Prerequisites

• C - Datatypes
• C - Operators
• C - Dereference operator (helpful)

Example

#include <stdio.h>

int main(void) {
  int a[3] = {10,20,30};
  for (int i = 0; i < 3; i++) printf("%d ", a[i]);
  printf("\n");
}

Common Pitfalls

• Indexing out of bounds is undefined behavior.
• Arrays are not resizable; use dynamic allocation if size varies.

Checks for Understanding

1. What is the type of a when passed to a function?

Expected Output

10 20 30 

Use Cases

• Buffers for I/O and networking.
• Lookup tables for algorithms.
• Fixed-size collections for embedded systems.

Exercises

1. Initialize an array of 5 integers to the first five squares and print them.
2. Find the minimum and maximum of an array in a single pass.