Golang 中的指针 - Pointer
package mainimport
"fmt"
type MyPoint struct {
X
int Y
int
}
func printFuncValue(p MyPoint){
p.X
= 1 p.Y
= 1 fmt.Printf(
" -> %v", p)
}
func printFuncPointer(pp
*MyPoint){ pp.X
= 1 // 实际上应该写做 (*pp).X，Golang 给了语法糖，减少了麻烦，但是也导致了 * 的不一致 pp.Y = 1
fmt.Printf(" -> %v", pp)
}
func (p MyPoint) printMethodValue(){
p.X += 1
p.Y += 1
fmt.Printf(" -> %v", p)
}
// 建议使用指针作为方法（method：printMethodPointer）的接收者（receiver：*MyPoint），一是可以修改接收者的值，二是可以避免大对象的复制
func (pp *MyPoint) printMethodPointer(){
pp.X += 1
pp.Y += 1
fmt.Printf(" -> %v", pp)
}
func main(){
p := MyPoint{0, 0}
pp := &MyPoint{0, 0}
fmt.Printf("\n value to func(value): %v", p)
printFuncValue(p)
fmt.Printf(" --> %v", p)
// Output: value to func(value): {0 0} -> {1 1} --> {0 0}
//printFuncValue(pp) // cannot use pp (type *MyPoint) as type MyPoint in argument to printFuncValue
//printFuncPointer(p) // cannot use p (type MyPoint) as type *MyPoint in argument to printFuncPointer
fmt.Printf("\n pointer to func(pointer): %v", pp)
printFuncPointer(pp)
fmt.Printf(" --> %v", pp)
// Output: pointer to func(pointer): &{0 0} -> &{1 1} --> &{1 1}
fmt.Printf("\n value to method(value): %v", p)
p.printMethodValue()
fmt.Printf(" --> %v", p)
// Output: value to method(value): {0 0} -> {1 1} --> {0 0}
fmt.Printf("\n value to method(pointer): %v", p)
p.printMethodPointer()
fmt.Printf(" --> %v", p)
// Output: value to method(pointer): {0 0} -> &{1 1} --> {1 1}
fmt.Printf("\n pointer to method(value): %v", pp)
pp.printMethodValue()
fmt.Printf(" --> %v", pp)
// Output: pointer to method(value): &{1 1} -> {2 2} --> &{1 1}
fmt.Printf("\n pointer to method(pointer): %v", pp)
pp.printMethodPointer()
fmt.Printf(" --> %v", pp)
// Output: pointer to method(pointer): &{1 1} -> &{2 2} --> &{2 2}
}
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