A struct, short for “structure,” is a way to bundle together multiple pieces of data with different types into a single entity. Unlike arrays, which store multiple values of the same type, structs allow different types to coexist within a single unit, making them useful for organizing related data.
Declaring a Struct
In Go, a struct is defined using the type keyword followed by the struct name and its members.
Syntax:
type structName struct { member1 datatype member2 datatype member3 datatype}Example:
Here, Motorcycle is a struct that groups multiple details about a motorcycle, such as brand, model, year, and price.
type Motorcycle struct { brand string model string year int price int}Each member of the struct can have a different data type. In this example, brand and model are strings, while year and price are integers.
Accessing Struct Members
To access the elements within a struct, use the dot (.) operator.
Example:
Below, two instances of the Motorcycle struct (bike1 and bike2) are created and their attributes are assigned values.
package mainimport ("fmt")type Motorcycle struct { brand string model string year int price int}func main() { var bike1 Motorcycle var bike2 Motorcycle // Assigning values to bike1 bike1.brand = "Yamaha" bike1.model = "R1" bike1.year = 2022 bike1.price = 15000 // Assigning values to bike2 bike2.brand = "Ducati" bike2.model = "Panigale V4" bike2.year = 2023 bike2.price = 25000 // Printing bike1 details fmt.Println("Brand: ", bike1.brand) fmt.Println("Model: ", bike1.model) fmt.Println("Year: ", bike1.year) fmt.Println("Price: $", bike1.price) // Printing bike2 details fmt.Println("Brand: ", bike2.brand) fmt.Println("Model: ", bike2.model) fmt.Println("Year: ", bike2.year) fmt.Println("Price: $", bike2.price)}Output:
Brand: YamahaModel: R1Year: 2022Price: $15000Brand: DucatiModel: Panigale V4Year: 2023Price: $25000Passing a Struct as a Function Argument
Structs can also be passed as arguments to functions, allowing for cleaner code when working with structured data.
Example:
The following program defines a function printMotorcycle() that takes a Motorcycle struct as an argument and prints its details.
package mainimport ("fmt")type Motorcycle struct { brand string model string year int price int}func main() { var bike1 Motorcycle var bike2 Motorcycle // Assigning values to bike1 bike1.brand = "Kawasaki" bike1.model = "Ninja ZX-10R" bike1.year = 2021 bike1.price = 18000 // Assigning values to bike2 bike2.brand = "Honda" bike2.model = "CBR1000RR" bike2.year = 2022 bike2.price = 20000 // Calling function to print details printMotorcycle(bike1) printMotorcycle(bike2)}func printMotorcycle(bike Motorcycle) { fmt.Println("Brand: ", bike.brand) fmt.Println("Model: ", bike.model) fmt.Println("Year: ", bike.year) fmt.Println("Price: $", bike.price)}Output:
Brand: KawasakiModel: Ninja ZX-10RYear: 2021Price: $18000Brand: HondaModel: CBR1000RRYear: 2022Price: $20000