7.指针入门

package main
import "fmt"
func changValue(p int){
    p=10;
}
func main() {
    var a int = 1;
    changValue(a)
    fmt.Println(a)  //1  值传递
}

package main
import "fmt"
func changValue(p *int){
    *p=10;
}
func main() {
    var a int = 1;
    changValue(&a) 
    fmt.Println(a)   //10
}

package main
import "fmt"
func swap(pa *int,pb *int)  {
    var temp int
    temp = *pa
    *pa = *pb
    *pb = temp
}
func main() {
    var a int = 10
    var b int = 20
    fmt.Println(a,b)   //  10  20
    swap(&a,&b)
    fmt.Println(a,b)   //  20  10
    var p *int
    p = &a
    fmt.Println(p)
    fmt.Println(&a)
}