Go語言之旅-go-tour練習答案
阿新 • • 發佈:2020-12-29
中文主頁
https://tour.go-zh.org/
控制流(flowcontrol)
迴圈與函式(flowcontrol/8)
簡版,迴圈十次退出
package main
import (
"fmt"
)
func Sqrt(x float64) float64 {
z := float64(1)
for i := 0; i <= 10; i++ {
z = z - (z*z - x) / (2 * z)
}
return z
}
func main() {
fmt. Println(Sqrt(2))
}
無限迴圈達到指定條件再退出
package main
import (
"fmt"
"math"
)
func Sqrt(x float64) float64 {
z := float64(1)
for {
y := z - (z*z - x) / (2 * z)
if math.Abs(y - z) < 1e-10 {
return y
}
z = y;
}
}
func main() {
fmt.Println(Sqrt(2))
fmt.Println(math.Sqrt(2))
}
更多型別(moretypes)
切片(moretypes/18)
package main
import "golang.org/x/tour/pic"
func Pic(dx, dy int) [][]uint8 {
myPic := make([][]uint8, dy)
for i:=0; i<dy; i++{
myPic[i] = make([]uint8, dx)
for j:=0; j<dx; j++ {
myPic[i][j] = uint8(i*j)
}
}
return myPic
}
func main() {
pic.Show(Pic)
}
影象:
- uint8(i*j)
- uint8((i+j)/2)
- uint8(i^j)
- uint8(i%(j+1))
- uint8(float64(i) * math.Log(float64(j)))
對映(moretypes/23)
package main
import (
"strings"
"golang.org/x/tour/wc"
)
func WordCount(s string) map[string]int {
// 定義返回的計數器
count := make(map[string]int)
// 獲取所有單詞的陣列
allStrings := strings.Fields(s)
for _, val := range allStrings {
// 計數
count[val]++
}
return count
}
func main() {
wc.Test(WordCount)
}
斐波納契閉包(moretypes/26)
package main
import "fmt"
// 返回一個“返回int的函式”
func fibonacci() func() int {
// 定義初始值
sum1 := 0
sum2 := 1
return func() int {
// 求和
sum := sum1 + sum2
// 更新
sum1 = sum2
sum2 = sum
return sum
}
}
func main() {
f := fibonacci()
for i := 0; i < 10; i++ {
fmt.Println(f())
}
}