The basis of the variables used GO

Go languages: statically typed language, variables (variable) is a clear type, the compiler also checks the correctness of the variable type.

First, the basic type

Declare variables: global variables must have the keyword var

var name [type] specify the data type

var is a keyword to declare a variable, name is the variable name, type is the type of the variable.
For example: var NUM_2 int = 10 ;

var name; do not specify the type of data, the specific data type inference by the system itself

var dg = "str"

var_name: = value does not specify the type of data, the specific data type inference by the system itself

dd := 1223

Batch statement:

was (
    str_1 int
    db    float64
)

 

The default value of the data

When a variable is declared, it is automatically given the value of zero types: int is 0, float to 0.0, bool is false, string is an empty string, the pointer is nil and the like. All memory is initialized in Go's.

Variable aliases

of the type (
     // to type an alias string str 
    str string 
    // to float64 type an alias Double 
    Double float64
)

func main() {
    // used as alias definition variable 
    var . Price Double = 123.3435
    std.Println(price)
    var name = STR " Joe Smith "
    std.Println(name)
}

 

Variable type conversion

Unlike the java language can go implicit conversion, he must be displayed

main FUNC () {
     var NUM float32 = 1.2 
    // will turn float32 int 
    var Bu int = int (NUM)
    std.Println(bu)
}

Second, the constant

Declaration syntax definitions and variables constant format similar to:const name [type] = value

const PI = 3.14159  // approximation corresponds to the math.Pi

Batch definitions

const (
    e   = 2.7182818 
    pi = 3.1415926 
)

iota constant generator
constant declaration can be used to initialize iota constant generator, which is used to generate a set of constants to initialize a similar rule, but do not write it again each line initialization expression. Const in a declaration statement, in the first line of the constant declaration where, iota will be set to 0, then add a line in each of a constant declaration.

const (
    Sunday = iota
    Monday
    Tuesday
    Wednesday
    Thursday
    Friday
    Saturday
)

func main() {
    std.Println(Sunday)
    std.Println(Monday)
    std.Println(Tuesday)
    std.Println(Wednesday)
    std.Println(Thursday)
    std.Println(Friday)
    std.Println(Saturday)
} 
Result:

0
1
2
3
4
5
6

 Second, the statement:

// 1, ################## for ############# 
    was fa int 
    for {
         if fa> 10 {
            std.Println("fa >10")
            break
        }
        FA ++
    }
    // 2, ################## for ############# 
    was FFA int = 12 
    for FFA> 10 {
        std.Println("ffa >10")
        LHW -
    }
    //3、##################for#############
    for i := 0; i < 3; i++ {
        std.Println("for")
    }

var flag bool
    if flag {
        std.Println("=======true=======")
    } else {
        std.Println("=======false=========")
    }
    if a := 4; a > 1 {
        std.Println(a)
    }