Catalog

1.go Functions of language

1.1 Define a function to return a value

Code section ：

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1.2 Define a function to return multiple values

Code section ：

The function returns 2 It's worth , How to accept only one value ？

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Function code summary ：

 2.go The pointer to language , A pointer cannot operate ,go Language parameter passing has only value passing , Address passing through pointers

Code section ：

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1.go Functions of language

1.1 Define a function to return a value

Code section ：

func eval(a, b int, op string) int { // Defined function eval,a,b Is a shaping parameter ,op Is a string parameter ,int Is the return value of the function 
	switch op {
	case "+":
		return a + b
	case "-":
		return a - b
	case "*":
		return a * b
	case "/":
		return a / b
	default:
		panic("unsupported op:" + op) // Used for error reporting 
	}
}

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1.2 Define a function to return multiple values

Code section ：

func div(a, b int) (q, r int) {
	return a / b, a % b
}

The function returns 2 It's worth , How to accept only one value ？

func main() {
	fmt.Println(eval(1, 2, "+"))
	q, r := div(13, 3)
	fmt.Println(q, r)
	// The function returns 2 It's worth , How to accept only one value ？
	a, _ := div(13, 3) // answer ： Replace another value with an underscore 
	fmt.Println(a)
}

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Function code summary ：

package main

import "fmt"

// The definition function returns a value 
func eval(a, b int, op string) int { // Defined function eval,a,b Is a shaping parameter ,op Is a string parameter ,int Is the return value of the function 
	switch op {
	case "+":
		return a + b
	case "-":
		return a - b
	case "*":
		return a * b
	case "/":
		return a / b
	default:
		panic("unsupported op:" + op) // Used for error reporting 
	}
}

// Define a function to return multiple values 
func div(a, b int) (q, r int) {
	return a / b, a % b
}
func main() {
	fmt.Println(eval(1, 2, "+"))
	q, r := div(13, 3)
	fmt.Println(q, r)
	// The function returns 2 It's worth , How to accept only one value ？
	a, _ := div(13, 3) // answer ： Replace another value with an underscore 
	fmt.Println(a)
}

 2.go The pointer to language , A pointer cannot operate ,go Language parameter passing has only value passing , Address passing through pointers

Code section ：

package main

import "fmt"

//go Language pointer , A pointer cannot operate 
//go The parameter passing of language is only value passing , Address passing through pointers 
func swap(a, b *int) {
	*b, *a = *a, *b
	// Or write directly as return b,a
}
func main() {
	var a int = 2
	var pa *int = &a
	*pa = 3
	fmt.Println(a)
	aa, bb := 1, 2
	swap(&aa, &bb)
	fmt.Println(aa, bb)
}

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End of this chapter