安装
brew install go
国际惯例hello,world.
创建文件hello.go go文件的main方法为函数的主入口，必须有这个方法。 hello.go
package main
import "fmt"
func main() {
fmt.Println("hello,go")
}
编译并运行文件
首先编译
go build hello.go
然后运行
go run hello.go
编译一次即可。
输入一个数字并运算
package main
import (
"fmt"
"math"
)
func main() {
fmt.Println("Circle Area calculation")
fmt.Print("Enter a radius value: ")
var radius float64
fmt.Scanf("%f", &radius) #可以接受控制台输入的数字
area := math.Pi * math.Pow(radius,2)
fmt.Printf("Circle area with radius %.2f = %.2f \n", radius,area)
}
变量声明和赋值
package main
import "fmt"
func main() {
// 声明变量，需要制定类型。
var str string
var n,m int
var mn float32
// 赋值
str="Hello World"
n=10
m=50
mn=2.45
fmt.Println("value of str= ",str)
fmt.Println("value of n=",n)
fmt.Println("value of m=",m)
fmt.Println("value of mn=",mn)
// 声明变量并赋值
var city string="London"
var x int =10
fmt.Println("value of city=",city)
fmt.Println("value of x=",x)
// 声明变量并赋默认值
contry :="DE"
contry="Hello"
val:=15
fmt.Println("value of contry",contry)
fmt.Println("value of val=",val)
/* 声明多个变量 */
var (
name string
email string
age int
)
name = "john"
email = "john@email.com"
age = 25
fmt.Println(name)
fmt.Println(email)
fmt.Println(age)
}
加减乘除
package main
import "fmt"
func main() {
// declare variables
var a,b int
// assign values
a = 5
b = 10
// arithmetic operation
// addition
c:=a + b
fmt.Printf("%d + %d = %d \n",a,b,c)
// subtraction
d:=a - b
fmt.Printf("%d - %d = %d \n",a,b,d)
// division
e:=float32(a) / float32(b)
fmt.Printf("%d / %d = %.2f \n",a,b,e)
// multiplication
f:=a * b
fmt.Printf("%d * %d = %d \n",a,b,f)
}
数学运算
package main
import (
"fmt"
"math"
)
func main() {
a := 2.4
b := 1.6
c := math.Pow(a,2)
fmt.Printf("%.2f^%d = %.2f \n",a,2,c)
c = math.Sin(a)
fmt.Printf("Sin(%.2f) = %.2f \n",a,c)
c = math.Cos(b)
fmt.Printf("Cos(%.2f) = %.2f \n",b,c)
c = math.Sqrt(a*b)
fmt.Printf("Sqrt(%.2f*%.2f) = %.2f \n",a,b,c)
}
条件语句if
package main
import "fmt"
func main() {
var (
a=5
b=8
)
/*
if{ #这个花括号必须紧邻if
do something
}else{ #else前后紧邻}和{
do something
}
}
*/
if a>b || a-b<a {
fmt.Println("condtional-->a>b || a-b<a")
}else{
fmt.Println("...another")
}
}
自增和自减
package main
import "fmt"
func main() {
// declare variables
var a = 4
// increment
fmt.Printf("a = %d \n",a)
a=a+1
fmt.Printf("a+1 = %d \n",a)
a++
fmt.Printf("a++ = %d \n",a)
// decrement
a = a - 1
fmt.Printf("a - 1 = %d \n",a)
a--
fmt.Printf("a-- = %d \n",a)
}
switch..case
/*
switch option{
case option1:
// do option1 job
case option2:
// do option2 job
}
*/
package main
import "fmt"
func main() {
selected := 2
switch selected{
case 0:
fmt.Println("selected = 0")
case 1:
fmt.Println("selected = 1")
default:
fmt.Println("other..")
}
}
for循环
/*
for initialization;condition;increment/decrement{
}
*/
package main
import "fmt"
func main() {
// iteration -for
var i int
for i=0;i<5;i++{
fmt.Println(i)
}
for j:=5;j<11;j++{
fmt.Println(j)
}
}
转载于:https://www.cnblogs.com/c-x-a/p/10343066.html
相关资源：Go语言学习笔记
