Function parameters - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

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

C

void printNumber([1] num) {
    printf("%d\n", num);
}

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

Aint

Bchar

Cfloat

Ddouble

Attempts:

3 left

💡 Hint

Common Mistakes

Using a floating-point type like float instead of int.

Using char which is for single characters.

The function parameter should be of type int to accept an integer.

2fill in blank

medium

Complete the function call to pass the variable correctly.

C

int value = 10;
printNumber([1]);

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

A&value

Bvalue&

C*value

Dvalue

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the address of the variable when the function expects a value.

Using pointer dereference incorrectly.

The function expects an integer value, so pass the variable value directly.

3fill in blank

hard

Fix the error in the function definition to accept two integer parameters.

C

void addNumbers(int a, [1] b) {
    printf("%d\n", a + b);
}

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

Afloat

Bint

Cchar

Ddouble

Attempts:

3 left

💡 Hint

Common Mistakes

Using different types for parameters that should be the same.

Using floating-point types when integers are expected.

Both parameters should be of type int to add two integers.

4fill in blank

hard

Fill both blanks to declare a function that returns the sum of two integers.

C

[1] add([2] a, int b) {
    return a + b;
}

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

Aint

Bfloat

Cvoid

Ddouble

Attempts:

3 left

💡 Hint

Common Mistakes

Using void as return type when a value is returned.

Using different types for parameters.

The function returns an int and both parameters are int types.

5fill in blank

hard

Fill all three blanks to declare and call a function that multiplies two floats and returns the result.

C

[1] multiply([2] x, [3] y) {
    return x * y;
}

float result = multiply(2.5f, 4.0f);

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

Afloat

Bint

Cdouble

Dvoid

Attempts:

3 left

💡 Hint

Common Mistakes

Using int or double instead of float.

Using void as return type when a value is returned.

The function returns a float and both parameters are float to multiply decimal numbers.

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 declare variables inside the main function

C. To print output on the screen

D. To create loops inside functions

Solution

1. Step 1: Understand function parameters

   Function parameters allow you to pass information into a function so it can use that data.

2. Step 2: Identify the correct purpose

   Creating loops inside functions, declaring variables inside the main function, and printing output on the screen describe other tasks, not the role of parameters.

3. Final Answer:

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

4. Quick Check:

   Function parameters = send data into functions [OK]

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

Common Mistakes:

• Confusing parameters with variables declared inside main
• Thinking parameters print output
• Mixing parameters with loop control

2. Which of the following is the correct way to declare a function with two integer parameters in C?

easy

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

B. void add(int a, b);

C. void add(int a int b);

D. void add(int a, int b);

Solution

1. Step 1: Check parameter syntax

   Parameters must be separated by commas and each must have a type and name.

2. Step 2: Identify correct syntax

   void add(int a, int b); correctly uses commas and types. void add(int a; int b); uses semicolon instead of comma. void add(int a int b); misses comma. void add(int a, b); misses type for second parameter.

3. Final Answer:

   void add(int a, int b); -> Option D

4. Quick Check:

   Parameters need type and comma [OK]

Hint: Separate parameters with commas and specify type for each [OK]

Common Mistakes:

• Using semicolons instead of commas between parameters
• Omitting type for parameters
• Missing commas between parameters

3. What will be the output of this C program?

void printSum(int x, int y) {
    printf("%d\n", x + y);
}

int main() {
    printSum(3, 4);
    return 0;
}

medium

A. 7

B. 34

C. 0

D. Compilation error

Solution

1. Step 1: Understand function call and parameters

   The function printSum receives 3 and 4 as parameters and adds them.

2. Step 2: Calculate the sum and output

   3 + 4 equals 7, so printf prints 7 followed by a newline.

3. Final Answer:

   7 -> Option A

4. Quick Check:

   3 + 4 = 7 [OK]

Hint: Sum parameters inside function to get output [OK]

Common Mistakes:

• Thinking parameters concatenate as strings
• Expecting zero output without return
• Assuming syntax error due to missing includes

4. Identify the error in this function declaration:

int multiply(int a, b) {
    return a * b;
}

medium

A. Return statement is incorrect

B. Function must return void

C. Missing type for parameter b

D. Function name is invalid

Solution

1. Step 1: Check parameter declarations

   Each parameter must have a type. Here, 'b' lacks a type.

2. Step 2: Confirm other parts are correct

   Return type int and function name are valid. Return statement syntax is correct.

3. Final Answer:

   Missing type for parameter b -> Option C

4. Quick Check:

   Every parameter needs a type [OK]

Hint: Declare type for every parameter explicitly [OK]

Common Mistakes:

• Omitting type for second or later parameters
• Assuming return type must be void
• Misreading return statement as error

5. You want to write a function that swaps two integers using pointers. Which function parameter list is correct?

hard

A. void swap(int &a, int &b)

B. void swap(int *a, int *b)

C. void swap(int a, int b)

D. void swap(int a*, int b*)

Solution

1. Step 1: Understand swapping with pointers

   To swap values in C, you pass pointers to the variables so the function can modify original data.

2. Step 2: Identify correct pointer syntax

   void swap(int *a, int *b) correctly declares two pointer parameters. void swap(int a, int b) passes by value (won't swap original). void swap(int &a, int &b) uses C++ reference syntax (invalid in C). void swap(int a*, int b*) has incorrect pointer syntax.

3. Final Answer:

   void swap(int *a, int *b) -> Option B

4. Quick Check:

   Use pointers to modify original variables [OK]

Hint: Use int * for pointer parameters to modify originals [OK]

Common Mistakes:

• Passing parameters by value when pointers are needed
• Using C++ reference syntax in C
• Incorrect pointer declaration syntax