Passing Arrays to Functions

Tutorial 2 of 5

1. Introduction

In this tutorial, we will explore how to pass arrays to functions in C++. By the end of this tutorial, you will be able to pass arrays to functions, manipulate array data inside functions, and understand how array data works in a function.

Prerequisites: Basic understanding of C++ syntax, function, and arrays.

2. Step-by-Step Guide

In C++, arrays can be passed to functions in three different ways, namely:

Pass-by-value
Pass-by-reference
Pass-by-pointer

When we pass an array to a function as an argument, the function works with the original array. This is because the array's address, not the actual data, is passed - this is known as 'pass by reference'.

3. Code Examples

Example 1: Pass-by-value

In this example, we will pass an array to a function and print the array elements.

#include <iostream>
using namespace std;

// Function to print array elements
void printArray(int arr[], int size) {
    for (int i = 0; i < size; i++) {
        cout << arr[i] << " ";
    }
    cout << endl;
}

int main() {
    int arr[] = {1, 2, 3, 4, 5};
    int size = sizeof(arr) / sizeof(arr[0]);
    printArray(arr, size); // Pass array to the function
    return 0;
}

This will output: 1 2 3 4 5

Example 2: Pass-by-reference

In this example, we will pass an array to a function and double the array elements.

#include <iostream>
using namespace std;

// Function to double array elements
void doubleArray(int arr[], int size) {
    for (int i = 0; i < size; i++) {
        arr[i] *= 2;
    }
}

int main() {
    int arr[] = {1, 2, 3, 4, 5};
    int size = sizeof(arr) / sizeof(arr[0]);
    doubleArray(arr, size); // Pass array to the function
    for (int i = 0; i < size; i++) {
        cout << arr[i] << " ";
    }
    cout << endl;
    return 0;
}

This will output: 2 4 6 8 10

4. Summary

In this tutorial, you have learned how to pass arrays to functions in C++. We have covered pass-by-value and pass-by-reference examples. You can now manipulate array data within functions and understand how this manipulation affects the original array.

5. Practice Exercises

Write a function that takes an array as an argument and finds the maximum value in the array.
Write a function that takes an array as an argument and reverses the array elements.

Solutions:

Maximum value in the array:

#include <iostream>
using namespace std;

// Function to find maximum value in array
int findMax(int arr[], int size) {
    int max = arr[0];
    for (int i = 1; i < size; i++) {
        if (arr[i] > max) {
            max = arr[i];
        }
    }
    return max;
}

int main() {
    int arr[] = {1, 2, 3, 4, 5};
    int size = sizeof(arr) / sizeof(arr[0]);
    cout << "Max value is: " << findMax(arr, size) << endl;
    return 0;
}

Reverse array elements:

#include <iostream>
using namespace std;

// Function to reverse array elements
void reverseArray(int arr[], int size) {
    int start = 0, end = size - 1;
    while (start < end) {
        swap(arr[start], arr[end]);
        start++;
        end--;
    }
}

int main() {
    int arr[] = {1, 2, 3, 4, 5};
    int size = sizeof(arr) / sizeof(arr[0]);
    reverseArray(arr, size); // Reverse array
    for (int i = 0; i < size; i++) {
        cout << arr[i] << " ";
    }
    cout << endl;
    return 0;
}

Keep on practicing and experimenting with different scenarios to strengthen your understanding. Happy coding!