package main
import "fmt"
// function add func add(a, b int) int { return a + b }
// 1 func testFunc1() {
// function "add" to var "f1"
// then "f1" is a function
f1 := add
// type of f1 = func(int int) int
fmt.Printf("type of f1 = %T\n", f1)
// call function "f1"
// params are 2 and 5
sum := f1(2, 5)
// sum = 7
fmt.Printf("sum = %d\n", sum)
}
// 2 func testFunc2() {
// anonymous function to var "f1", then "f1" is a function
f1 := func(a, b int) int {
return a + b
}
// type of f1 = function(int, int) int
fmt.Printf("type of f1 = %T\n", f1)
// call function f1, params are 2 and 5
sum := f1(2, 5)
// sum = 7
fmt.Printf("sum = %d\n", sum)
}
// 3 func testFunc3() { var i = 0
// the statement after "defer" will be pushed into stack first
// so the value of var "i" will be "0"
// defer i = 0
defer fmt.Printf("defer i = %d\n", i)
i = 100
// i = 100
fmt.Printf("i = %d\n", i)
return
}
// 4 func testFunc4() { var i = 0
// the anonymous function after "defer" will be pushed into stack first
// but at this time, the statement in function will not be pushed into stack
// so at this time the value of var "i" is not specific
// the value of var
// at the end the value of var "i" is 100
defer func() {
fmt.Printf("defer i = %d\n", i)
}()
i = 100
// i = 100
fmt.Printf("i = %d\n", i)
return
}
func main() { //testFunc1() //testFunc2() //testFunc3() testFunc4() }
