Multiple return values in Go - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

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

Look at this Go function that returns two values. What will be printed?

Go

package main
import "fmt"

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

func main() {
    q, r := divide(10, 3)
    fmt.Println(q, r)
}

A Error: cannot use divide(10, 3) in multiple assignment

B 3 0

C 3 3

D 3 1

💡 Hint

Remember that the first return value is the quotient and the second is the remainder.

The function divides 10 by 3. The quotient is 3 and the remainder is 1, so it prints "3 1".

❓ Predict Output

intermediate

What happens when you ignore one return value in Go?

What will this program print?

Go

package main
import "fmt"

func getValues() (int, string) {
    return 42, "hello"
}

func main() {
    val, _ := getValues()
    fmt.Println(val)
}

A 42

B hello

C Compilation error due to unused variable

D 42 hello

💡 Hint

The underscore (_) is used to ignore a return value.

The second return value is ignored using _, so only 42 is printed.

❓ Predict Output

advanced

What is the output of this Go function returning named values?

Check the named return values and what the function returns.

Go

package main
import "fmt"

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

func main() {
    a, b := swap(5, 10)
    fmt.Println(a, b)
}

A 5 10

B 10 5

C 0 0

D Compilation error: missing return values

💡 Hint

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

The function swaps the values by assigning named returns and returns them implicitly, so output is "10 5".

❓ Predict Output

advanced

What error does this Go code produce when returning multiple values?

What error will this code cause?

Go

package main

func foo() (int, int) {
    return 1
}

func main() {}

A syntax error: unexpected newline

B missing return at end of function

C cannot use 1 (type int) as type (int, int) in return statement

D no error, compiles fine

💡 Hint

Check the number of values returned compared to the function signature.

The function expects two return values but only returns one, causing a type mismatch error.

🧠 Conceptual

expert

How many values does this Go function return and what are their types?

Analyze this function signature and tell how many values it returns and their types.

Go

func process(data []int) (sum int, avg float64, err error) {
    // implementation omitted
    return
}

A Three values: int, float64, and error

B Two values: int and float64

C Three values: int, int, and error

D One value: a struct containing int, float64, and error

💡 Hint

Look at the named return values and their types carefully.

The function returns three values: sum (int), avg (float64), and err (error).