package main

import "fmt"

type Person3 struct {
	Name string
	Age  int
}

// sliceEscape 切片元素为指针，且切片被返回，元素逃逸
func sliceEscape() []*Person3 {
	var people []*Person3
	for i := 0; i < 3; i++ {
		person := &Person3{Name: fmt.Sprintf("Person3%d", i), Age: 20 + i}
		people = append(people, person) // person 逃逸
	}
	return people
}

// dynamicSlice 切片动态扩容，底层数组逃逸
func dynamicSlice() []int {
	s := make([]int, 0) // 编译期无法确定最终容量
	for i := 0; i < 100; i++ {
		s = append(s, i) // 扩容时底层数组逃逸
	}
	return s
}

// mapEscape 映射值为指针，值逃逸
func mapEscape() map[string]*Person3 {
	m := make(map[string]*Person3)
	m["alice"] = &Person3{Name: "Alice", Age: 25} // 指针值逃逸
	return m
}

func main() {
	people := sliceEscape()
	fmt.Printf("切片元素逃逸：%d个Person\n", len(people))

	s := dynamicSlice()
	fmt.Printf("切片扩容逃逸：len=%d, cap=%d\n", len(s), cap(s))

	m := mapEscape()
	fmt.Printf("映射值逃逸：%+v\n", *m["alice"])
}