Accessing struct fields in Go - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of accessing struct fields

What is the output of this Go program?

Go

package main
import "fmt"
type Person struct {
    Name string
    Age  int
}
func main() {
    p := Person{Name: "Alice", Age: 30}
    fmt.Println(p.Name, p.Age)
}

A 30 Alice

B Person{Name: "Alice", Age: 30}

C Name: Alice, Age: 30

D Alice 30

💡 Hint

Remember how to access fields of a struct using dot notation.

The struct fields are accessed using dot notation. fmt.Println prints the values of Name and Age separated by space.

❓ Predict Output

intermediate

Output when accessing nested struct fields

What will this Go program print?

Go

package main
import "fmt"
type Address struct {
    City string
}
type Person struct {
    Name    string
    Address Address
}
func main() {
    p := Person{Name: "Bob", Address: Address{City: "Paris"}}
    fmt.Println(p.Address.City)
}

A Paris

B Bob

C Address{City: "Paris"}

D City: Paris

💡 Hint

Access nested struct fields by chaining dot notation.

The field City is inside Address, which is inside Person. Access it as p.Address.City.

❓ Predict Output

advanced

Output when accessing pointer to struct fields

What is the output of this Go program?

Go

package main
import "fmt"
type Car struct {
    Brand string
}
func main() {
    c := &Car{Brand: "Toyota"}
    fmt.Println(c.Brand)
}

A &{Toyota}

B Toyota

C Brand: Toyota

D Compilation error

💡 Hint

Go lets you access struct fields through pointers directly.

In Go, you can access fields of a struct through a pointer using dot notation without explicit dereferencing.

❓ Predict Output

advanced

Output when accessing uninitialized struct fields

What will this Go program print?

Go

package main
import "fmt"
type User struct {
    Username string
    Active   bool
}
func main() {
    var u User
    fmt.Println(u.Username, u.Active)
}

A nil false

B Compilation error

C "" false

D Username Active

💡 Hint

Uninitialized struct fields have zero values.

String zero value is empty string "" and bool zero value is false.

🧠 Conceptual

expert

Understanding field promotion in embedded structs

Given the following Go code, what is the output of the program?

Go

package main
import "fmt"
type Animal struct {
    Name string
}
type Dog struct {
    Animal
    Breed string
}
func main() {
    d := Dog{Animal: Animal{Name: "Buddy"}, Breed: "Beagle"}
    fmt.Println(d.Name)
}

A Buddy

B Dog{Name: "Buddy", Breed: "Beagle"}

C Beagle

D Compilation error: ambiguous field

💡 Hint

Embedded structs promote their fields to the outer struct.

The embedded struct Animal's field Name is promoted to Dog, so d.Name accesses Animal.Name.