C# work with functions
<p>I'am new with C#. How works in C# functions?</p>

<p>My try:</p>

<pre><code>        private void Form1_Load(object sender, EventArgs e)
    {
        MessageBox.Show(Convert.ToString(number_p(5)));            
    }

    public void number_p(int number)
    {
        int one = 1;
        number = number + one;
        return number;
    }
</code></pre>

<p>Error: return, why?
Thanks</p>
