Return values in Go - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Go function with multiple return values?

Consider the following Go code. What will be printed when main runs?

Go

package main
import "fmt"

func divideAndRemainder(a, b int) (int, int) {
    return a / b, a % b
}

func main() {
    q, r := divideAndRemainder(17, 5)
    fmt.Println(q, r)
}

A 2 3

B 3 3

C 3 2

D Error: cannot return two values

💡 Hint

Remember that / is integer division and % is remainder.

The function returns the quotient and remainder of dividing 17 by 5. 17 divided by 5 is 3 with remainder 2, so the output is 3 2.

❓ Predict Output

intermediate

What does this Go function return when called?

Look at this Go function and its call. What is the output?

Go

package main
import "fmt"

func greet(name string) string {
    return "Hello, " + name + "!"
}

func main() {
    message := greet("Alice")
    fmt.Println(message)
}

A Hello, Alice!

B Hello Alice!

C Error: missing return statement

D greet Alice

💡 Hint

Check the string concatenation and punctuation.

The function returns the greeting string with a comma and exclamation mark exactly as shown, so the output is Hello, Alice!.

❓ Predict Output

advanced

What is the output of this Go function with named return values?

Analyze this Go code using named return values. What will it print?

Go

package main
import "fmt"

func swap(a, b int) (x int, y int) {
    x = b
    y = a
    return
}

func main() {
    a, b := 10, 20
    x, y := swap(a, b)
    fmt.Println(x, y)
}

A 20 10

B Compilation error: missing return values

C 0 0

D 10 20

💡 Hint

Named return values can be returned by just return without arguments.

The function swaps the values by assigning to named return variables and returns them implicitly. So output is 20 10.

❓ Predict Output

advanced

What error does this Go function produce?

What error will occur when running this Go code?

Go

package main

func add(a, b int) int {
    return a + b
    return a - b
}

func main() {}

A Runtime error: multiple returns

B Syntax error: unreachable code after return

C No error, returns sum

D Compilation error: missing return statement

💡 Hint

Check if code after a return statement is allowed.

In Go, code after a return statement in the same block is unreachable, causing a syntax error.

🧠 Conceptual

expert

How many values does this Go function return?

Consider this Go function signature. How many values does it return?

func process(data []int) (result int, err error)

A Three values: int, error, and a boolean

B One value: a struct containing int and error

C No values, only modifies data in place

D Two values: an int and an error

💡 Hint

Look at the parentheses and types in the return signature.

The function returns two values: an int named result and an error named err.