1.4.25 Defining Methods With Multiple Parameters

A Method Can Receive More Than One Piece of Information

You have already worked with a method that accepts one parameter:

public void SetJerseyNumber(int number)
{
    this.jerseyNumber = number;
}

A method can also accept multiple parameters when one behavior needs several input values.

For example, a Player method might need both a name and a jersey number.

Separate Parameters with Commas

A method declaration can be:

public void SetPlayerInfo(string name, int jerseyNumber)
{
    this.name = name;
    this.jerseyNumber = jerseyNumber;
}

The parameter list contains:

string name
int jerseyNumber

A comma separates the parameters.

Each Parameter Has Its Own Type and Name

For:

string name

the type is:

string

and the parameter name is:

name

For:

int jerseyNumber

the type is:

int

and the parameter name is:

jerseyNumber

Each input is defined independently.

The Caller Supplies One Argument for Each Parameter

A matching call is:

player1.SetPlayerInfo("Jordan", 7);

Conceptually:

Activity diagram showing "Jordan" name, then 7 jerseyNumber. — JordanName.

The arguments correspond to the parameters in their declared positions.

Argument Order Matters

Given:

public void SetPlayerInfo(string name, int jerseyNumber)

this call matches the intended order:

player1.SetPlayerInfo("Jordan", 7);

The first argument supplies name.

The second supplies jerseyNumber.

A method call must respect the parameter structure defined by the method.

Use Parameters That Belong to One Method Purpose

Multiple parameters are useful when the information supports one focused behavior.

For example:

SetPlayerInfo(string name, int jerseyNumber)

has one clear purpose:

Avoid building a method with many unrelated parameters simply because C# allows it.

Single-purpose method design still matters.

Parameters Are Method Variables

Inside:

public void SetPlayerInfo(string name, int jerseyNumber)
{
    this.name = name;
    this.jerseyNumber = jerseyNumber;
}

the parameter names:

name
jerseyNumber

belong to the current method call.

The fields:

this.name
this.jerseyNumber

belong to the current Player object's state.

The assignments transfer incoming values into object state.

The Same Method Can Be Reused

For example:

player1.SetPlayerInfo("Jordan", 7);
player2.SetPlayerInfo("Casey", 1);

The method design stays the same.

Each call supplies a different set of arguments.

This lets one method represent a reusable behavior.

Multiple Parameters Can Use Different Types

A method might need:

public void SetStatus(string position, bool available)
{
    this.position = position;
    this.isAvailable = available;
}

The first parameter receives text.

The second receives Boolean state.

Each argument must be compatible with its corresponding parameter type.

Keep Current Examples Direct

Later Learning Activities show more advanced ways values can reach parameters, including forwarding arguments and passing returned values.

For now, focus on the direct relationship:

Activity diagram showing call with several arguments, then matching parameter list, then method uses those values. — CallWithSeveralArguments.

Read the Method Signature as a Contract

For:

SetPlayerInfo(string name, int jerseyNumber)

read:

That interpretation makes both method definitions and calls easier to reason about.