C++ Array to Function

The C++, you can pass an array to a function in several ways. When passing an array to a function, it’s essential to understand that arrays are treated as pointers to their first elements. Here are the common methods to pass an array to a function:

Method 1: Pass by Pointer

You can pass an array to a function by passing a pointer to its first element. This method allows the function to modify the original array.

void printArray(int* arr, int size) {
    for (int i = 0; i < size; ++i) {
        std::cout << arr[i] << " ";
    }
    std::cout << std::endl;
}

int main() {
    int myArray[] = {1, 2, 3, 4, 5};
    int size = sizeof(myArray) / sizeof(myArray[0]);

    printArray(myArray, size);

    return 0;
}

Method 2: Pass by Reference

You can also pass an array by reference to a function, which allows the function to modify the original array. This is often preferred in C++.

void modifyArray(int (&arr)[5]) {
    for (int i = 0; i < 5; ++i) {
        arr[i] *= 2;
    }
}

int main() {
    int myArray[] = {1, 2, 3, 4, 5};

    modifyArray(myArray);

    for (int i = 0; i < 5; ++i) {
        std::cout << myArray[i] << " ";
    }
    std::cout << std::endl;

    return 0;
}

Method 3: Use a Pointer and Specify Array Size

You can pass an array by using a pointer along with specifying the array size as a separate parameter.

void printArray(int* arr, int size) {
    for (int i = 0; i < size; ++i) {
        std::cout << arr[i] << " ";
    }
    std::cout << std::endl;
}

int main() {
    int myArray[] = {1, 2, 3, 4, 5};
    int size = sizeof(myArray) / sizeof(myArray[0]);

    printArray(myArray, size);

    return 0;
}

Method 4: Use std::array or std::vector

In modern C++, you can use std::array or std::vector from the C++ Standard Library, which provide better safety and flexibility compared to traditional C-style arrays. These containers can be passed to functions like other data types.

#include <iostream>
#include <array>
#include <vector>

void printArray(const std::array<int, 5>& arr) {
    for (int element : arr) {
        std::cout << element << " ";
    }
    std::cout << std::endl;
}

void printVector(const std::vector<int>& vec) {
    for (int element : vec) {
        std::cout << element << " ";
    }
    std::cout << std::endl;
}

int main() {
    std::array<int, 5> myArray = {1, 2, 3, 4, 5};
    std::vector<int> myVector = {1, 2, 3, 4, 5};

    printArray(myArray);
    printVector(myVector);

    return 0;
}

Using std::array or std::vector is often recommended in modern C++ because they provide better safety and maintainability compared to raw arrays.