Go Learning notes: 1.1 variables

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/**data:2015-06-02*author:qdx*note:go language Learning Note: variable */package mainimport "FMT" Variable type//go language:/*boolstringint int8 int16 Int32 int64uint uint8 uint16 uint32 uint64uintptrbyte (equivalent to uint8) Rune (equivalent to Int32, used to represent a Unicode code point) float32 float64c       Omplex64 Complex128*///1.go language, the definition of a variable is the beginning of Var, followed by the variable name and type, can not be defined repeatedly//a;   Error, variable not defined//var A; Error, no add variable type, and no initial value (the initial value can be regarded as stealth declaration) var a int = 5;//2. Any structure outside the function (construct) begins with a keyword, such as variable//amount starting with the Var keyword, and the function starts with the FUNC keyword//a   = 6;  Error, the function outside the body does not define the statement//a: = 6;  Error: The left of = does not define a new variable, the function is outside the body of the non-defined statement//b: = 6; Error, the function outside the body of the non-definition statement, must start with the keyword//var b: = 6;  Error, syntax errors, define variable initialization with "=" instead of ": =" var b = 6;//g: = 9; Error, you must start with the keyword//3. When defining a variable, you can use only one Var, and the definition of all variables in parentheses var (c int = 8;d int = 9;e = 10;f string = "Hello";)//var I, j, k = 10, 20 ;  When the definition is initialized, the number of left and right parameters must be the same as Var I, j, k = ten, 30;//var l int, m string;       //4 cannot be defined in the same row when the type is inconsistent. The variable definition in the body of a function can not start with Var, func test () {//b: = 8; All variables in the body of the function must be used, otherwise the error is, the function body can be defined as Var a, b int = 10, 20;   Variables in the body of the function can be overridden within the scope of the function to override the variable//var a = 50 in the function body;        Error, the function body has a repeating definition g: = 10; //The function body can define the variable without VAR, at which time it has been//g: = "Hello"//variable definition, the type is determined, if you need to assign different types of values to the defined variables, you need to cast//g = int (6.5);     Error, cannot convert character constant to type var h = 6.5;g = Int (h); To cast the variable correctly, the type conversion of the variable must be the displayed T (Var) fmt. Println (a); fmt. Println (b); fmt. Println (f); fmt. Println (e+10);//fmt. Println (e+ "a"); Error FMT. Println (g);} Func Testconst () {///Test constants//function body constants can not be used, the constants defined within the function are used only within the function,//Beyond the definition of the constant function scope, the scope of the constant disappears const PI = 3.14const (A = 5;c = "Golang" ;)}func Main () {test (); Testconst (); fmt. Println ("C:", c); return;}