一起来学go 13.指针

指针

指针值类型有

• int系列
• float系列
• bool
• string
• 数组
• 结构体struct

demo01

package main  
import "fmt"  //引入一个包 'fmt'
func main() {
	var num1 int = 99
	//num1的内存地址，&num1
	fmt.Println("num1的内存地址：",&num1)

	num1=200
	fmt.Println("num1的内存地址：",&num1)
}

demo02

package main  
import "fmt"  //引入一个包 'fmt'
func main() {
	var num1 int = 99
	//num1的内存地址，&num1
	fmt.Println("num1的内存地址：",&num1)

	//指针变量num2
	//1.num2的类型*int
	//2.num2的值&num1
	var num2 *int = &num1
    fmt.Printf("num2=%v\n",num2)
	fmt.Println("num2的内存地址：",&num2)
}

demo03

package main  
import "fmt"  //引入一个包 'fmt'
func main() {
	var num1 int = 99
	//num1的内存地址，&num1
	fmt.Println("num1的内存地址：",&num1)
	//指针变量num2
	//1.num2的类型*int
	//2.num2的值&num1
	var num2 *int = &num1
    fmt.Printf("num2=%v\n",num2)
	fmt.Println("num2的内存地址：",&num2)
	//取出指针里内存地址指向的值
	fmt.Printf("num2指针指向的值%v\n",*num2)
}

demo04

package main  
import "fmt"  //引入一个包 'fmt'
func main() {
	var num1 int = 199
	//num1的内存地址，&num1
	fmt.Printf("num1的值位%v\n",num1)
	fmt.Println("num1的内存地址：",&num1)
	//指针变量num2
	//1.num2的类型*int
	//2.num2的值&num1
	var num2 *int = &num1
    fmt.Printf("num2=%v\n",num2)
	fmt.Println("num2的内存地址：",&num2)
	//取出指针里内存地址指向的值
	fmt.Printf("num2指针指向的值%v\n",*num2)
	//修改指针的值，num1也会发生修改
	*num2 = 999
	fmt.Printf("num2指针指向的值%v\n",*num2)
	fmt.Printf("num1的值位%v\n",num1)
}

demo05

package main  
import "fmt"  //引入一个包 'fmt'
func main() {
	var num1 int = 199
	var num2 int = 299
	var ptr * int
	ptr = &num1
	*ptr = 100
	ptr = &num2
	*ptr = 200
	fmt.Printf("num1=%v,num2=%v,ptr=%v",num1,num2,*ptr)
}