Method parameters in Java - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a method that takes one integer parameter.

Java

public void printNumber([1] number) {
    System.out.println(number);
}

Drag options to blanks, or click blank then click option'

Aint

Bdouble

CString

Dboolean

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong data type like String or boolean for an integer parameter.

The method parameter must be of type int to accept an integer.

2fill in blank

medium

Complete the code to call the method with the correct argument.

Java

printNumber([1]);

Drag options to blanks, or click blank then click option'

A"5"

B5

Ctrue

D5.0

Attempts:

3 left

💡 Hint

Common Mistakes

Passing a string like "5" instead of an integer.

Passing a floating-point number like 5.0.

The method expects an integer argument, so passing 5 (an int) is correct.

3fill in blank

hard

Fix the error in the method declaration to accept two parameters: an integer and a string.

Java

public void display([1] number, String text) {
    System.out.println(number + ": " + text);
}

Drag options to blanks, or click blank then click option'

Aint

Bdouble

Cboolean

DString

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong type like String or double for the integer parameter.

The first parameter should be int to accept an integer value.

4fill in blank

hard

Fill both blanks to declare a method that takes a double and a boolean parameter.

Java

public void setValues([1] value, [2] flag) {
    System.out.println(value + ", " + flag);
}

Drag options to blanks, or click blank then click option'

Adouble

Bint

Cboolean

DString

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up the types or using incorrect types like int or String.

The method parameters are double for a decimal number and boolean for true/false values.

5fill in blank

hard

Fill all three blanks to declare a method that takes a String, an int, and a boolean parameter.

Java

public void update([1] name, [2] age, [3] active) {
    System.out.println(name + ", " + age + ", " + active);
}

Drag options to blanks, or click blank then click option'

Aint

Bboolean

CString

Ddouble

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping the order of types or using wrong types for parameters.

The parameters are String for name, int for age, and boolean for active status.

Practice

1. What is the purpose of method parameters in Java?
public void greet(String name) { ... }

easy

A. To declare variables inside the method

B. To define the method's return type

C. To send data into methods so they can use it inside

D. To specify the method's access level

Solution

1. Step 1: Understand method parameters

   Method parameters are variables listed in the method definition that accept values when the method is called.

2. Step 2: Identify their purpose

   They allow sending data into the method so it can perform actions using that data.

3. Final Answer:

   To send data into methods so they can use it inside -> Option C

4. Quick Check:

   Parameters pass data into methods [OK]

Hint: Parameters pass info into methods for flexible use [OK]

Common Mistakes:

• Confusing parameters with return types
• Thinking parameters declare variables inside method body
• Mixing parameters with access modifiers

2. Which of the following is the correct syntax to declare a method with two parameters in Java?

easy

A. public void add(int a; int b) { }

B. public void add(int a, int b) { }

C. public void add(int a int b) { }

D. public void add(int a & int b) { }

Solution

1. Step 1: Recall parameter syntax

   Parameters are listed inside parentheses separated by commas, each with a type and name.

2. Step 2: Check each option

   public void add(int a, int b) { } uses commas correctly; others use semicolon, missing comma, or invalid symbol.

3. Final Answer:

   public void add(int a, int b) { } -> Option B

4. Quick Check:

   Parameters separated by commas [OK]

Hint: Parameters must be comma-separated with type and name [OK]

Common Mistakes:

• Using semicolons instead of commas
• Omitting commas between parameters
• Using invalid symbols like &

3. What will be the output of this Java code?

public class Test {
  public static void printSum(int x, int y) {
    System.out.println(x + y);
  }
  public static void main(String[] args) {
    printSum(5, 3);
  }
}

medium

A. 8

B. 53

C. x + y

D. Compile error

Solution

1. Step 1: Understand method call with parameters

   The method printSum is called with 5 and 3 as arguments, assigned to x and y.

2. Step 2: Calculate the sum inside the method

   Inside printSum, it prints x + y which is 5 + 3 = 8.

3. Final Answer:

   8 -> Option A

4. Quick Check:

   5 + 3 = 8 [OK]

Hint: Sum parameters values to get output [OK]

Common Mistakes:

• Concatenating numbers as strings
• Expecting variable names printed
• Thinking code won't compile

4. Identify the error in this method declaration:

public void displayMessage(String message, int) {
  System.out.println(message);
}

medium

A. Parameter list missing variable name for int type

B. Method must return a value

C. Cannot use String as parameter type

D. System.out.println is invalid here

Solution

1. Step 1: Check parameter list syntax

   Each parameter must have a type and a variable name. Here, int has no name.

2. Step 2: Identify the error

   Missing variable name after int causes a syntax error.

3. Final Answer:

   Parameter list missing variable name for int type -> Option A

4. Quick Check:

   Parameters need type and name [OK]

Hint: Every parameter needs a name after its type [OK]

Common Mistakes:

• Omitting parameter names
• Thinking return type is missing
• Misunderstanding print statement usage

5. You want to create a method that calculates the area of a rectangle. Which method signature correctly uses parameters to accept the rectangle's width and height as doubles?

hard

A. public void area(double width; double height)

B. public double area(width, height)

C. public double area(int width, int height)

D. public double area(double width, double height)

Solution

1. Step 1: Identify correct parameter types and syntax

   The method should accept two double parameters named width and height, separated by commas.

2. Step 2: Evaluate each option

   public double area(double width, double height) correctly declares two double parameters with names and commas; public double area(width, height) misses types; public double area(int width, int height) uses int instead of double; public void area(double width; double height) uses semicolon instead of comma and void return type.

3. Final Answer:

   public double area(double width, double height) -> Option D

4. Quick Check:

   Parameters need type, name, comma-separated [OK]

Hint: Use type and name with commas for parameters [OK]

Common Mistakes:

• Omitting parameter types
• Using wrong separators like semicolons
• Using wrong data types for precision