How to use golang interface

In Golang, an interface (Interface) is a type that defines the set of methods that an object should have. Using interfaces allows us to describe objects in an abstract way without worrying about the specific implementation of the object.

The declaration format of the interface is as follows:

type interface name interface {

方法1(参数1 类型1, 参数2 类型2, ...) (返回值1 类型1, 返回值2 类型2, ...)
方法2(参数1 类型1, 参数2 类型2, ...) (返回值1 类型1, 返回值2 类型2, ...)
...

}

Among them, the interface name can be any legal identifier; method Can have zero or more parameters and zero or more return values, and the types of parameters and return values ​​can be any type, including interface types.

The following is a simple example that demonstrates how to define an interface and use it to describe two different types:

package main

import "fmt"

// Define the interface
type Shape interface {

Area() float64

}

// Define the structure Circle
type Circle struct {

X, Y, Radius float64

}

// Define the method Area() to implement the Shape interface
func (c Circle) Area() float64 {

return 3.14 * c.Radius * c.Radius

}

// Define the structure Rectangle
type Rectangle struct {

X1, Y1, X2, Y2 float64

}

// Define the method Area() to implement the Shape interface
func (r Rectangle) Area() float64 {

return (r.X2 - r.X1) * (r.Y2 - r.Y1)

}

// Define the function GetArea, which accepts a Shape type parameter and calls its Area() method
func GetArea(shape Shape) float64 {

return shape.Area()

}

func main() {

// 创建一个 Circle 对象并计算它的面积
c := Circle{0, 0, 5}
fmt.Println(GetArea(c)) // 输出：78.5

// 创建一个 Rectangle 对象并计算它的面积
r := Rectangle{0, 0, 10, 10}
fmt.Println(GetArea(r)) // 输出：100

// 注意：Circle 和 Rectangle 类型都实现了 Shape 接口，因此可以作为参数传递给 GetArea 函数

}

In the above example, we defined an interface named Shape and defined two different Types Circle and Rectangle, they all implement the Area() method of the Shape interface. We also define a function called GetArea that accepts a parameter of type Shape and calls its Area() method to calculate the area.

In the main function, we created a Circle object and a Rectangle object respectively, and passed them to the GetArea function to calculate their areas. Since both the Circle and Rectangle types implement the Shape interface, they can both be passed as parameters to the GetArea function to calculate the area.

In short, interface is a very important concept in Golang. It allows us to describe objects in an abstract way without worrying about the specific implementation of the object. By mastering the use of interfaces, we can better design and write Golang code.

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