C# out parameter

The out keyword is used to declare output parameters in method or function signatures. The output parameter is a parameter that is used to return multiple values from a method. The output parameters are used to pass data out of a method. But a normal function is used for passing the data inside function.

out is used to state that the parameter passed must be modified by the method.

C# out parameter

Syntax of out parameter

returnType methodName(parameters, out dataType outputParameter)
{

// Method body

// The method assigns a value to outputParameter

// ...

}

Basic Structure Of out Parameter

  • Output Parameter:

    An out parameter is an output parameter, which means its value is expected to be set by the method. When the method is called, it must assign a value to the out parameter before the method returns.

  • Initialization Not Required:

    Unlike regular parameters, you don't need to initialize an out parameter before passing it to the method. The method is responsible for initializing it.

  • Multiple Outputs:

    It is an option variable that you passed in function between parentheses () and and may include one or more parameter declarations, separated by commas.Each parameter consists of a data type and a parameter name.

out parameter in C# with example

  • Example

    Here in below example, we have Sum function that is having out parameter of int type and similarly we have another function with named Multiply that also have out parameter of int type.

using System;
class CSharpProgram
{
static void Main(string[] arge)
{
void Sum(int price1, int price2, out int sum)
{
sum = price1 + price2;
}
void Multiply(int price1, int price2, out int multiply)
{
multiply = price1 * price2;
}

int x = 10, y = 5;
int resultSum,resultmultiply;
Sum(x,y,out resultSum);
Console.WriteLine("Sum is="+ resultSum);
Multiply(x,y,out resultmultiply);
Console.WriteLine("Multiply is="+ resultmultiply);
}
}


Output

Sum is = 15
Multiple is = 50

  • out parameter example deccription in C#:

Here's a basic breakdown of how out parameter work in C# in above example:
using System;

using System; is namespace of C# that required to run the above program.

CSharpProgram

We have defined a class CSharpProgram that will contain function or methods.

static void Main(string[] arge)

It is a main entry point of the program.
void Sum(int price1, int price2, out int sum)

We have defined a method Sum that have void return type and receving 3 integer parameter with named of price1 , price2 and sum . This function have one out type parameter of int type with named sum. This function is doing sum of two integer parameters (price1, price2). and will return the sum in result as out parameter.

void Multiply(int price1, int price2, out int multiply)

We have defined a method Multiply that have void return type and receving 3 integer parameter with named of price1 , price2 and multiply . This function have one out type parameter of int type with named multiply. This function is doing multiply of two integer parameters (price1, price2). and will return the multiply in result as out parameter.

int x = 10, y = 5;

we have declared and initialized two int vairavle with named x = 10, y = 5 respectively.

int resultSum,resultmultiply;

we have declared two int vairavle with named resultSum, resultmultiply respectively. These parameters will be passed with out keyword to it's related function.

Sum(x,y,out resultSum);

Here we are calling Sum function with 3 parameters. x and y are simple int type parameter and resultSum is out paramteter that will get the changed from it's related function.
Console.WriteLine("Sum is="+ resultSum);

Here we are printing the result of the Sum function.

Multiply(x,y,out resultmultiply);

Here we are calling Multiply function with 3 parameters. x and y are simple int type parameter and resultmultiply is out paramteter that will get the changed from it's related function.

Console.WriteLine("Multiply is="+ resultmultiply);

Here we are printing the result of the Multiply function.

Summary

The output parameters are assigned values before it completes its execution. If a method with output parameters does not assign values to them before returning, it will result in a compilation error.

Previous C# ref parameter
Next C# in keyword parameter

Related Articles

Related Article C# ref parameter
Related Article C# out parameter
Related Article C# in keyword parameter
Related Article C# Function with Examples
Choose Your Options
RTL Version
Boxed Version
Want Sticky Header
Dark Verion
Purchase now $17
You will find much more options and styling in admin panel.
TOP