Method overloading in C Sharp (C#) - Step-by-Step Execution

Concept Flow - Method overloading

Call method with arguments

↓

Check method name

↓

Match argument types/count

↓

Call matched method

↓

Execute method

↓

Return result

When you call a method, the program looks for the same method name with matching argument types and count, then runs that specific version.

Execution Sample

C Sharp (C#)

class Calculator {
  public int Add(int a, int b) {
    return a + b;
  }
  public int Add(int a, int b, int c) {
    return a + b + c;
  }
}

Calculator calc = new Calculator();
int result1 = calc.Add(2, 3);
int result2 = calc.Add(1, 4, 5);

This code shows two Add methods with different numbers of parameters. The program chooses which Add to run based on how many numbers you give.

Execution Table

Step	Method Called	Arguments	Match Found?	Action	Output
1	Add	(2, 3)	Yes (Add(int, int))	Execute Add(int, int)	5
2	Add	(1, 4, 5)	Yes (Add(int, int, int))	Execute Add(int, int, int)	10
3	Add	(2)	No	Error: No matching method	None

💡 Execution stops after matching method runs or error if no match.

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3
result1	undefined	5	5	5
result2	undefined	undefined	10	10

Key Moments - 2 Insights

Why does the program choose the Add method with two parameters when I call Add(2, 3)?

Because in the execution_table row 1, the method Add(int, int) matches exactly the two arguments (2, 3), so it runs that version.

What happens if I call Add with one number like Add(2)?

As shown in execution_table row 3, no Add method matches one argument, so the program gives an error.

Visual Quiz - 3 Questions

Look at the execution_table, what is the output when calling Add(1, 4, 5)?

A 10

B 5

C Error

D None

💡 Hint

Check execution_table row 2 for the output of Add(1, 4, 5).

At which step does the program fail to find a matching method?

A Step 1

B Step 2

C Step 3

D No failure

💡 Hint

Look at execution_table row 3 where no match is found.

If you add a method Add(int a), what would happen when calling Add(2)?

A It will still give an error

B It will call Add(int a) and return 2

C It will call Add(int, int)

D It will call Add(int, int, int)

💡 Hint

Refer to the concept_flow where matching argument count and types decides the method.

Concept Snapshot

Method overloading means having multiple methods with the same name but different parameters.
When you call the method, the program picks the one matching the number and types of arguments.
If no match is found, you get an error.
This helps write cleaner code with similar actions but different inputs.

Full Transcript

Method overloading allows a class to have multiple methods with the same name but different parameters. When you call a method, the program checks the method name and looks for a version with matching argument types and count. If it finds one, it runs that method. If not, it gives an error. For example, a Calculator class can have Add methods with two or three numbers. Calling Add(2, 3) runs the two-parameter version and returns 5. Calling Add(1, 4, 5) runs the three-parameter version and returns 10. Calling Add(2) causes an error because no matching method exists. This feature helps keep code simple and organized when similar actions need different inputs.

Practice

1.

What is method overloading in C#?

easy

A. Changing the return type of a method without changing parameters

B. Using methods from a parent class in a child class

C. Having multiple methods with the same name but different parameters

D. Writing methods that call themselves recursively

Solution

1. Step 1: Understand method naming

   Method overloading means using the same method name multiple times.

2. Step 2: Check parameter differences

   Each overloaded method must have different parameters (type or count).

3. Final Answer:

   Having multiple methods with the same name but different parameters -> Option C

4. Quick Check:

   Method overloading = Same name, different parameters [OK]

Hint: Same method name but different parameters means overloading [OK]

Common Mistakes:

• Confusing overloading with overriding
• Thinking return type alone allows overloading
• Believing parameter names must differ

2.

Which of the following is correct syntax for method overloading in C#?

public void Print(int x) { }
public void Print(string x) { }

easy

A. Both methods have the same name but different parameter types

B. Methods must have different names to overload

C. Return types must be different for overloading

D. Parameter names must be different for overloading

Solution

1. Step 1: Check method names

   Both methods are named 'Print', which is allowed for overloading.

2. Step 2: Check parameter types

   One method takes an int, the other a string, so parameters differ.

3. Final Answer:

   Both methods have the same name but different parameter types -> Option A

4. Quick Check:

   Same name + different parameters = valid overloading [OK]

Hint: Overloaded methods differ by parameter types or count, not names [OK]

Common Mistakes:

• Thinking parameter names affect overloading
• Believing return type difference is enough
• Assuming method names must be unique

3.

What will be the output of this C# code?

class Program {
  static void Display(int x) { Console.WriteLine("Int: " + x); }
  static void Display(string x) { Console.WriteLine("String: " + x); }
  static void Main() {
    Display(5);
    Display("Hello");
  }
}

medium

A. Compilation error due to ambiguous call

B. Int: 5\nString: Hello

C. String: 5\nInt: Hello

D. Runtime error

Solution

1. Step 1: Identify which Display method is called

   Display(5) calls Display(int x), printing "Int: 5".

2. Step 2: Identify second method call

   Display("Hello") calls Display(string x), printing "String: Hello".

3. Final Answer:

   Int: 5\nString: Hello -> Option B

4. Quick Check:

   Overloaded methods called by matching parameter type [OK]

Hint: Calls match method by parameter type exactly [OK]

Common Mistakes:

• Assuming ambiguous call error
• Mixing output order
• Expecting runtime error

4.

Find the error in this code snippet:

class Test {
  void Show(int x) { }
  void Show(int x) { }
}

medium

A. Return types differ so no error

B. No error, code compiles fine

C. Parameter names must differ for overloading

D. Methods have the same signature causing a compile error

Solution

1. Step 1: Check method signatures

   Both methods are named 'Show' and take one int parameter, so signatures are identical.

2. Step 2: Understand overloading rules

   Overloading requires different parameter types or counts; identical signatures cause errors.

3. Final Answer:

   Methods have the same signature causing a compile error -> Option D

4. Quick Check:

   Same name + same parameters = error [OK]

Hint: Overloaded methods must differ in parameters, not just names [OK]

Common Mistakes:

• Thinking return type difference matters
• Assuming parameter names affect overloading
• Believing code compiles fine

5.

You want to create a class with a method Calculate that can add two integers, two doubles, or concatenate two strings. Which method signatures correctly implement method overloading?

hard

A. void Calculate(int a, int b), void Calculate(double a, double b), void Calculate(string a, string b)

B. int Calculate(int a, int b), int Calculate(int a, int b), string Calculate(string a, string b)

C. void Calculate(int a, int b), void Calculate(int a), void Calculate(string a, string b)

D. void Calculate(int a, int b), void Calculate(double a), void Calculate(string a)

Solution

1. Step 1: Check parameter types and counts

   void Calculate(int a, int b), void Calculate(double a, double b), void Calculate(string a, string b) has three methods named Calculate with different parameter types but same count (2).

2. Step 2: Verify overloading rules

   Different parameter types allow overloading; all methods differ by parameter type.

3. Final Answer:

   void Calculate(int a, int b), void Calculate(double a, double b), void Calculate(string a, string b) -> Option A

4. Quick Check:

   Same name, different parameter types = valid overloading [OK]

Hint: Overload by changing parameter types or count, not return type [OK]

Common Mistakes:

• Using same parameters with different return types
• Changing parameter count incorrectly
• Confusing overloading with overriding