C++ array to function

Arrays in C++ :

Instead of defining distinct variables for each item, arrays are used to hold numerous values in a single variable.

An array can be declared by specifying the variable type, then the array and then the square brackets that would store the number of elements in the array.

Syntax:

var_type array[no_of_elements]

Example –

String colors[3] = {“red”, “blue”, “green”}

The above example shows an array of colors having 3 colors namely red, blue and green.

Functions in C++ :

A function is a code block that only executes when it is invoked.

The Parameters are data that may be sent into a function.

Functions are used to accomplish certain tasks and are essential for code reuse: Once the code is defined, it may be reused numerous times.

Syntax:

void func(){
	//the piece of code that is to be executed
}

Example –

void func(){
	cout << “This is executed”
}
int main(){
	func(); // function called
	Return 0;
}

Output:

This is executed

In this example, we created a function called func(), which when called in main gave us the required output that it is executed.

Passing Arrays to Function in C++ :

Arrays can be passed as arguments to functions in C++. We can also return arrays from functions.

Make sure you understand C++ Arrays and C++ Functions before learning about providing arrays as a function argument.

Syntax :

returnType functName(datatype arr[size]){
	// code block
}

Example –

int sum(int score[4]) {
	// code block
}

In this Example, the method sum has been supplied an int type array named score(). The array has a size of 4.

1D Array to a Function:

In the C++ language, a one-dimensional array is the most basic type of array. A one-dimensional array is simple to define, initialise, and modify. A one-dimensional array can be used as a function argument and so on.

Example -

// C++ Program to show score of 4 students


#include <iostream>
using namespace std;


// declaring function to show score
//1d array taken as parameter
void show(int s[4]) {
    cout << "Showing marks: " << endl;


    // showing elements of the array    
    for (int k = 0; k < 4; ++k) {
        cout << "Person " << k + 1 << ": " << s[k] << endl;
    }
}


int main() {


    // call and initialize array
    int score[4] = {77,98,91,69};
    
    // call show func
    // pass array as arg
    show(score);


    return 0;
}

Output :

Showing score:
Person 1: 77
Person 2: 98
Person 3: 91
Person 4: 69

In this example,

1. Only the name of the array is used when calling a function with an array as a parameter.

show(score);

The memory location of the first member of array score[4] is represented by the parameter score.

2. However, take note of the show() function's argument.

void show(int s[4])

In this case, we utilise the whole array declaration in the function argument, including the square brackets [].

3. The int s[4] function argument is converted to int* s;. This corresponds to the same address as the array score. This indicates that we're actually modifying the original array score when we manipulate s[4] in the method body.

This is how C++ handles sending an array to a function to save memory and time.

Multi-dimensional Array to Function :

Multidimensional arrays may be simply defined as an array of arrays in C/C++. Tabular format is used to store data in multidimensional arrays (in row-major order).

Multidimensional arrays can also be sent as an argument to the function. As an example

Example –

// C++ Program to display the elements of two
// dimensional array by passing it to a function


#include <iostream>
using namespace std;


// define func 
// pass 2D array as parameter
void show(int no[][2]) {
    cout << "Showing Values: " << endl;
    for (int k = 0; k < 3; ++k) {
        for (int l = 0; l < 2; ++l) {
            cout << "number[" << k << "][" << l << "]: " << no[k][l] << endl;
        }
    }
}


int main() {


    // initializing the 2D array
    int number[3][2] = {
        {1, 2},
        {3, 4},
        {5, 6}
    };


    // call the func
    // pass 2D array as arg
    show(number);


    return 0;
}

Output:

Showing Values:
number[0][0]: 1
number[0][1]: 2
number[1][0]: 3
number[1][1]: 4
number[2][0]: 5
number[2][1]: 6

In this example, we've defined a function called show() in the previous program. The function accepts a two-dimensional array as an input, int no[][2], and outputs the array's elements.

We merely supply the name of the two-dimensional array as the function parameter display when invoking the function (number).

The number of rows in the array does not have to be specified. The number of columns, on the other hand, should always be stated. We used int no[][2] for this reason.

As a function parameter, we may also send arrays with more than two dimensions.