C# Passing an Array to a Function

Summary: in this tutorial, you’ll learn how to pass an array to a function as an argument.

Passing an array to a function as an argument #

To pass an array to a function, you specify the array parameter with the following syntax:

type [] arrayParameter

The following illustrates how to pass an array to a function:

void PrintArray(decimal[] elements)
{
    foreach (var element in elements)
    {
        Console.WriteLine($"{element:0.##}");
    }
}


decimal[] salaries = { 100000, 120000, 150000 };

PrintArray(salaries);

Output:

100000
120000
150000

How it works.

First, define a function called PrintArray() that outputs the elements of an array to the console:

void PrintArray(decimal[] elements)
{
    foreach (var element in elements)
    {
        Console.WriteLine($"{element:0.##}");
    }
}

In this PrintArray() function, we use the foreach statement to iterate over the elements of the array and output each of them to the console.

Second, declare a decimal array and initialize it with some values:

decimal[] salaries = { 100000, 120000, 150000 };

Third, pass the salaries array to the PrintArray() function:

PrintArray(salaries);

Note that you can initialize and pass a new array to the function in one step like this:

PrintArray(new decimal[]{ 100000, 120000, 150000 });

Changing the array elements #

Because arrays are reference types, the function can change the values of their elements. For example:

void PrintArray(decimal[] elements)
{
    foreach (var element in elements)
    {
        Console.WriteLine($"{element:0.##}");
    }
}

void Increase(decimal[] salaries, decimal percentage = 0.05m)
{
    for (int i = 0; i < salaries.Length; i++)
    {
        salaries[i] = salaries[i] * (1 + percentage);
    }
}

decimal[] salaries = { 100000, 120000, 150000 };

Console.WriteLine("Before increment:");
PrintArray(salaries);

Increase(salaries);

Console.WriteLine("After increment:");
PrintArray(salaries);

Output:

Before increment:
100000
120000
150000
After increment:
105000
126000
157500

How it works.

First, define the Increase() function that increases the elements of salaries array by a percentage. By default, the percentage is 5% (or 0.05):

void Increase(decimal[] salaries, decimal percentage = 0.05m)
{
    for (int i = 0; i < salaries.Length; i++)
    {
        salaries[i] = salaries[i] * (1 + percentage);
    }
}

Next, declare and initialize an array of salaries:

decimal[] salaries = { 100000, 120000, 150000 };

Then, output the elements of the salaries array using the PrintArray() function:

Console.WriteLine("Before increment:");
PrintArray(salaries);

After that, pass the salaries array to the Increase() function:

Increase(salaries);

Finally, output the elements of the salaries array to the console:

Console.WriteLine("After increment:");
PrintArray(salaries);

Summary #

Arrays are reference types, functions can change the values of the array elements.

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