Function parameters in Go - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a function with one integer parameter named x.

Go

func printNumber([1] int) {
    fmt.Println(x)
}

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

Anumber

Bnum

Cvalue

Dx

Attempts:

3 left

💡 Hint

Common Mistakes

Using a parameter name different from the one used inside the function causes an error.

The parameter name must be x to match the usage inside the function.

2fill in blank

medium

Complete the code to declare a function that takes two string parameters: first and last.

Go

func fullName([1] string, last string) string {
    return first + " " + last
}

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

Afirst

Bname

Cfname

Dlast

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different parameter name than the one used in the function body.

The first parameter must be named first to match the return statement.

3fill in blank

hard

Fix the error in the function parameter declaration to accept a float64 parameter named price.

Go

func calculateTax([1] float64) float64 {
    return price * 0.1
}

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

Aprice

Btax

Camount

Dcost

Attempts:

3 left

💡 Hint

Common Mistakes

Using a parameter name different from the one used inside the function causes an undefined variable error.

The parameter name must be price to match its usage inside the function.

4fill in blank

hard

Fill both blanks to declare a function that takes an int parameter age and a string parameter name.

Go

func greet([1] int, [2] string) string {
    return fmt.Sprintf("Hello %s, you are %d years old", name, age)
}

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

Aage

Byears

Cname

Dperson

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping parameter names or using names not matching the function body.

The parameters must be named age and name to match their usage in the Sprintf call.

5fill in blank

hard

Fill all three blanks to declare a function that takes a string parameter title, an int parameter pages, and a float64 parameter price.

Go

func bookInfo([1] string, [2] int, [3] float64) string {
    return fmt.Sprintf("%s has %d pages and costs $%.2f", title, pages, price)
}

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

Atitle

Bpages

Cprice

Dcost

Attempts:

3 left

💡 Hint

Common Mistakes

Using parameter names that do not match the variables used inside the function.

The parameter names must be title, pages, and price to match their usage in the Sprintf call.

Practice

1. What is the purpose of function parameters in Go?

easy

A. To print output from a function

B. To create new functions automatically

C. To stop a function from running

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

Solution

1. Step 1: Understand what parameters do

   Parameters let you give information to a function when you call it.

2. Step 2: Identify the correct purpose

   Sending data into functions makes them flexible and reusable with different inputs.

3. Final Answer:

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

4. Quick Check:

   Function parameters = send data into functions [OK]

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

Common Mistakes:

• Thinking parameters create functions
• Confusing parameters with output
• Believing parameters stop function execution

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

easy

A. func add(a, b int) int {}

B. func add(a int, b) int {}

C. func add(int a, int b) int {}

D. func add(a int b int) int {}

Solution

1. Step 1: Review Go function parameter syntax

   In Go, you can group parameters of the same type like a, b int.

2. Step 2: Identify correct syntax

   func add(a, b int) int {} groups same type parameters correctly. func add(a int, b) int {} misses type for b. func add(int a, int b) int {} places types before names. func add(a int b int) int {} lacks commas.

3. Final Answer:

   func add(a, b int) int {} -> Option A

4. Quick Check:

   Group same type params: a, b int [OK]

Hint: Group same type params with commas before type [OK]

Common Mistakes:

• Writing types before variable names (like C)
• Missing commas between parameters (like D)
• Forgetting type for second parameter (like B)

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

package main
import "fmt"
func greet(name string) {
    fmt.Println("Hello, " + name)
}
func main() {
    greet("Alice")
}

medium

A. Hello,

B. Hello, Alice

C. Hello, name

D. Compilation error

Solution

1. Step 1: Understand function call with parameter

   The function greet takes a string parameter name and prints "Hello, " plus that name.

2. Step 2: Check the argument passed

   In main, greet("Alice") is called, so name is "Alice".

3. Final Answer:

   Hello, Alice -> Option B

4. Quick Check:

   Function prints "Hello, " + argument [OK]

Hint: Function prints greeting plus passed name [OK]

Common Mistakes:

• Confusing parameter name with string literal
• Expecting no output
• Thinking it causes error without return

4. Identify the error in this Go function declaration:

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

func main() {
    result := multiply(3)
    fmt.Println(result)
}

medium

A. Function multiply called with wrong number of arguments

B. Missing import for fmt package

C. Return type missing in multiply function

D. Variable result not declared

Solution

1. Step 1: Check function call arguments

   The function multiply requires two int parameters, but it is called with only one argument 3.

2. Step 2: Identify the error

   This causes a compile-time error due to wrong number of arguments.

3. Final Answer:

   Function multiply called with wrong number of arguments -> Option A

4. Quick Check:

   Function call args must match parameters [OK]

Hint: Count arguments to match parameters exactly [OK]

Common Mistakes:

• Ignoring missing import for fmt (not shown here)
• Thinking return type is missing
• Assuming variable declaration error

5. Given this Go function:

func sumAndProduct(a, b int) (int, int) {
    return a + b, a * b
}

func main() {
    s, p := sumAndProduct(4, 5)
    fmt.Println(s, p)
}

What will be the output when the program runs?

hard

A. 20 9

B. 9

C. 9 20

D. Compilation error due to missing return

Solution

1. Step 1: Understand multiple return values

   The function sumAndProduct returns two integers: sum and product of a and b.

2. Step 2: Check values for inputs 4 and 5

   Sum is 4 + 5 = 9, product is 4 * 5 = 20. These are assigned to s and p.

3. Step 3: Print output

   fmt.Println(s, p) prints "9 20".

4. Final Answer:

   9 20 -> Option C

5. Quick Check:

   Multiple returns print sum then product [OK]

Hint: Multiple returns unpacked in order [OK]

Common Mistakes:

• Swapping sum and product values
• Expecting single return value
• Thinking missing return error