Passing Parameters in C#

In this article, we will learn about different ways to pass parameters to a functions in C#.

C# Call By Value

In C#, value-type parameters are that pass a copy of original value to the function rather than reference. It does not modify the original value. A change made in passed value does not alter the actual value. In the following example, we have pass value during function call.

Example:

using System;
namespace CallByValue {
    class Program {
        // User defined function  
        public static void Show(int val) {
            val *= val; // Manipulating value  
            Console.WriteLine("Value inside the show function " + val);
            // No return statement  
        }
        // Main function, execution entry point of the program  
        static void Main(string[] args) {
            int val = 50;
            Console.WriteLine("Value before calling the function " + val);
            Show(val); // Calling Function by passing value            
            Console.WriteLine("Value after calling the function " + val);
        }
    }
}

Output:

Value before calling the function 50

Value inside the show function 2500

Value after calling the function 50

C# Call By Reference

C# provides a ref keyword to pass argument as reference-type. It passes reference of arguments to the function rather than copy of original value. The changes in passed values are permanent and modify the original variable value.

Example:

using System;
namespace CallByReference {
    class Program {
        // User defined function  
        public static void Show(ref int val) {
            val *= val; // Manipulating value  
            Console.WriteLine("Value inside the show function " + val);
            // No return statement  
        }
        // Main function, execution entry point of the program  
        static void Main(string[] args) {
            int val = 50;
            Program program = new Program(); // Creating Object  
            Console.WriteLine("Value before calling the function " + val);
            Show(ref val); // Calling Function by passing reference            
            Console.WriteLine("Value after calling the function " + val);
        }
    }
}

Output:

Value before calling the function 50

Value inside the show function 2500

Value after calling the function 2500

C# Out Parameter

C# provides out keyword to pass arguments as out-type. It is like reference-type, except that it does not require variable to initialize before passing. We must use out keyword to pass argument as out-type. It is useful when we want a function to return multiple values.

Example 1:

using System;
namespace OutParameter {
    class Program {
        // User defined function  
        public static void Show(out int val) // Out parameter  
        {
            int square = 5;
            val = square;
            val *= val; // Manipulating value  
        }
        // Main function, execution entry point of the program  
        static void Main(string[] args) {
            int val = 50;
            Console.WriteLine("Value before passing out variable " + val);
            Show(out val); // Passing out argument  
            Console.WriteLine("Value after recieving the out variable " + val);
        }
    }
}

Output:

Value before passing out variable 50

Value after receiving the out variable 25

The following example demonstrates that how a function can return multiple values.

Example 2:

using System;
namespace OutParameter {
    class Program {
        // User defined function  
        public static void Show(out int a, out int b) // Out parameter  
        {
            int square = 5;
            a = square;
            b = square;
            // Manipulating value  
            a *= a;
            b *= b;
        }
        // Main function, execution entry point of the program  
        static void Main(string[] args) {
            int val1 = 50, val2 = 100;
            Console.WriteLine("Value before passing \n val1 = " + val1 + " \n val2 = " + val2);
            Show(out val1, out val2); // Passing out argument  
            Console.WriteLine("Value after passing \n val1 = " + val1 + " \n val2 = " + val2);
        }
    }
}

Output:

Value before passing

val1 = 50

val2 = 100

Value after passing

val1 = 25

val2 = 25

Task

In the editor below, perform the different tasks as directed.

Create two different functions:

• func1: Takes an integer as an input (without reference), and changes its value to 2.
• func2: Takes an integer as an input (with reference), and changes its value to 2.

Then, compare if the both the values after passing them to the functions are equal or not.
If equal, print True, else print False.
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