Function parameters in C++ - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a function that takes an integer parameter named x.

C++

void printNumber([1]) {
    std::cout << x << std::endl;
}

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

Aint

Bx int

Cint x

Dnumber

Attempts:

3 left

💡 Hint

Common Mistakes

Writing the parameter name before the type.

Omitting the parameter name.

Using a variable name without a type.

The correct way to declare a function parameter is by specifying the type followed by the variable name, like int x.

2fill in blank

medium

Complete the function call to pass the integer 5 to the function printNumber.

C++

printNumber([1]);

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

Aint

Bx

C"5"

D5

Attempts:

3 left

💡 Hint

Common Mistakes

Passing a string instead of an integer.

Passing the parameter name instead of a value.

When calling a function, you pass the actual value. Here, 5 is an integer literal.

3fill in blank

hard

Fix the error in the function definition by completing the parameter list correctly.

C++

void add([1]) {
    std::cout << a + b << std::endl;
}

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

Aa int, b int

Bint a, int b

Cint a b

Dint a; int b

Attempts:

3 left

💡 Hint

Common Mistakes

Using semicolons instead of commas.

Writing parameter names before types.

Omitting commas between parameters.

Function parameters must be separated by commas, each with a type and name: int a, int b.

4fill in blank

hard

Fill both blanks to declare a function that takes a float and a char parameter.

C++

void process([1], [2]) {
    // function body
}

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

Afloat value

Bint number

Cchar letter

Ddouble data

Attempts:

3 left

💡 Hint

Common Mistakes

Using int instead of float.

Using double instead of float.

Mixing up parameter types.

The function parameters are float value and char letter to match the required types.

5fill in blank

hard

Fill all three blanks to create a function that returns the sum of two integers and one float.

C++

auto sum([1], [2], [3]) {
    return a + b + c;
}

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

Aint a

Bint b

Cfloat c

Ddouble d

Attempts:

3 left

💡 Hint

Common Mistakes

Using double instead of float.

Using wrong parameter names.

Missing parameter types.

The function parameters are int a, int b, and float c to match the sum operation.

Practice

1.

What is the purpose of function parameters in C++?

easy

A. To send data into functions so they can use it

B. To define the return type of a function

C. To declare variables inside the function body

D. To specify the function's name

Solution

1. Step 1: Understand function parameters

   Function parameters are variables listed in the function definition that receive values when the function is called.

2. Step 2: Identify their purpose

   They allow the function to work with different data each time it is called, making the function flexible and reusable.

3. Final Answer:

   To send data into functions so they can use it -> Option A

4. Quick Check:

   Function parameters = input data for functions [OK]

Hint: Parameters pass data into functions for reuse [OK]

Common Mistakes:

• Confusing parameters with return types
• Thinking parameters declare variables inside function body
• Believing parameters define function name

2.

Which of the following is the correct syntax to declare a function add that takes two int parameters a and b?

easy

A. int add(int a, int b);

B. int add(a int, b int);

C. int add(int a; int b);

D. int add(int a b);

Solution

1. Step 1: Recall correct parameter syntax

   In C++, parameters are declared as type name pairs separated by commas inside parentheses.

2. Step 2: Check each option

   int add(int a, int b); correctly uses int a, int b. Options A, B, and C have syntax errors like missing comma, wrong order, or semicolon.

3. Final Answer:

   int add(int a, int b); -> Option A

4. Quick Check:

   Parameters = type name, comma separated [OK]

Hint: Parameters need type and name, separated by commas [OK]

Common Mistakes:

• Swapping type and name order
• Using semicolons instead of commas
• Omitting commas between parameters

3.

What will be the output of the following code?

void greet(std::string name) {
    std::cout << "Hello, " << name << "!" << std::endl;
}

int main() {
    greet("Alice");
    return 0;
}

medium

A. Compilation error

B. Hello, name!

C. Hello, !

D. Hello, Alice!

Solution

1. Step 1: Understand function call with parameter

   The function greet takes a string parameter name and prints "Hello, " plus the value of name.

2. Step 2: Check the argument passed

   In main, greet is called with "Alice", so name becomes "Alice".

3. Final Answer:

   Hello, Alice! -> Option D

4. Quick Check:

   Parameter value replaces variable in output [OK]

Hint: Function prints parameter value passed in call [OK]

Common Mistakes:

• Thinking parameter name prints literally
• Expecting empty output if parameter unused
• Assuming syntax error due to string parameter

4.

Identify the error in this function declaration:

void printSum(int a, b) {
    std::cout << a + b << std::endl;
}

medium

A. Parameters should be inside square brackets

B. Missing type for parameter b

C. Function must return int

D. Function name is invalid

Solution

1. Step 1: Check parameter declarations

   Each parameter must have a type and a name. Here, b has no type specified.

2. Step 2: Identify correct syntax

   The correct declaration is void printSum(int a, int b). Missing type causes a syntax error.

3. Final Answer:

   Missing type for parameter b -> Option B

4. Quick Check:

   Every parameter needs a type [OK]

Hint: Each parameter must have a type before its name [OK]

Common Mistakes:

• Omitting type for second or later parameters
• Assuming return type must be int
• Using wrong brackets for parameters

5.

Consider this function that calculates the area of a rectangle:

double area(double width, double height) {
    return width * height;
}

How would you call this function to calculate the area of a rectangle with width 5.0 and height 3.0, and store the result in a variable result?

hard

A. double result = area(width=5.0, height=3.0);

B. double result = area(3.0, 5.0);

C. double result = area(5.0, 3.0);

D. double result = area(5, 3);

Solution

1. Step 1: Understand parameter order and types

   The function expects width first, then height, both as doubles.

2. Step 2: Check each call option

   double result = area(5.0, 3.0); passes 5.0 as width and 3.0 as height correctly. double result = area(3.0, 5.0); swaps them. double result = area(width=5.0, height=3.0); uses invalid named arguments (not supported in C++). double result = area(5, 3); passes ints which convert but less precise.

3. Final Answer:

   double result = area(5.0, 3.0); -> Option C

4. Quick Check:

   Call with correct order and types [OK]

Hint: Match argument order and types exactly [OK]

Common Mistakes:

• Swapping argument order
• Using named arguments (not valid in C++)
• Passing wrong types without conversion