C# Out Parameter

In this chapter you will learn:
  • What is Output parameter in C sharp?
  • What is the advantage of Out parameter?
  • How to use Out parameter in C# programming?

C# out parameter is such type of parameter that is declared with out keyword. It is the same as reference parameter, that doesn’t create memory allocation.

Why use out parameter in C#?

Usually, a method returns value with return keyword. Unfortunately, a return modifier can return only one value at a time. Sometime, your C# program required to return multiple values from a single method. In this situation, you need such type of function that can produce multiple output result from a single function. The output parameter C# lets your program to return multiple values.


Programming examples of out parameter C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace out_parameter
    class Program
        //Accept two input parameter and returns two out value
        public static void rect(int len, int width, out int area, out int perimeter)
            area = len * width;
            perimeter = 2 * (len + width);
        static void Main(string[] args)
            int area, perimeter;
            // passing two parameter and getting two returning value
            Program.rect(5, 4, out area, out perimeter);
            Console.WriteLine("Area of Rectangle is {0}\t", area);
            Console.WriteLine("Perimeter of Rectangle is {0}\t", perimeter);


Area of Rectangle is 20
Perimeter of Rectangle is 18 __

In the preceding example, we created a method that accepts two input parameter and returns two out value.


In this chapter you learned about what is out parameter and how to use out parameter in C# programming. In next chapter you will learn about Command Line Argument in C#.

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