C++ Arrays

What Is an Array in C++?

An array in C++ is a container that holds several values of the same type using a single name. It's like having multiple drawers labeled with one tag, where each drawer can hold a different value — but all values are of the same kind (like all integers or all characters).

Why Use Arrays?

• Organizes similar values under one identifier
• Makes it simple to loop through multiple elements
• Offers fast access using index numbers
• Reduces the need for repeated variable declarations

Instead of creating five separate variables (int a, b, c, d, e), one array like int nums[5]; stores them all under one label.

Array Declaration Syntax

type arrayName[size];

• type: The data kind you want to store (e.g., int, float, char)
• arrayName: The label you assign to the array
• size: Total number of slots it can hold

Example

#include <iostream>  

int main() {     
      int scores[3] = {85, 90, 78};      

     for (int i = 0; i < 3; i++) {         
            std::cout << "Score " << i + 1 << ": " << scores[i] << "\n";    
     }      

    Return 0; 
} 

Explanation

• int scores[3]: Creates an array for three numbers.
• {85, 90, 78}: These are the initial stored values.
• The for loop displays each item using its position.
• scores[0] gives 85, scores[1] gives 90, and so on.

Array Indexing

• Arrays start counting from zero.
• The first element is at index 0, not 1.
• Accessing an element uses square brackets like arrayName[position].
• Trying to access beyond the declared size can cause unexpected behavior (undefined or memory errors).

Types of Arrays

2D Array Example

#include <iostream>  

int main() {     
      int grid[2][2] = {         
            {1, 2},         
            {3, 4}    
      };      
 
     for (int row = 0; row < 2; row++) {         
          for (int col = 0; col < 2; col++) {             
                  std::cout << grid[row][col] << " ";         
           }         
           std::cout << "\n";     
     }      

     return 0; 
} 

Explanation

• grid[2][2] sets up a square with two rows and two columns.
• Nested for loops cycle through each spot.

Values shown:

1 2   
3 4 

Character Array Example

#include <iostream>  

int main() {     
       char word[6] = {'H', 'e', 'l', 'l', 'o', '\0'};     
       std::cout << word;     
      return 0; 
} 

• This holds letters forming "Hello".
• \0 is the null character, marking the end of the text.

Summary

Arrays in C++ give you the power to manage collections of data using structured, compact, and consistent logic. Whether you’re handling scores, letters, or a full matrix — arrays let you group and control similar data under one roof. They're fast, clean, and essential for any serious coding in C++.