The initial experience of "class" struct in go

// Other packages ................. // Teacher01 can only be referenced in this file. The lower-case type teacher01 struct {ID int name string course string sex string} // teacher02 can be referenced in any file, uppercase type teacher02 struct {ID int name string course string sex string} // Note: // 1) when accessing teacher01, err, cannot refer to unexported name package name. teacher01 // 2) when accessing teacher02.sex, err, implicit assignment of unexported field 'sex' in package name. teacher02 literal // 3) When teacher02.sex is modified, an error is reported when sex is modified. // err, struct variable. sex undefined (cannot refer to unexported field or method sex)

// Code_015_struct_firsttime Project main. gopackage mainimport ("FMT") type student struct {ID int name string sex byte age int ADDR string} func printstudentvalue (TMP student) {TMP. id = 250 FMT. println ("printstudentvalue TMP =", TMP)} func main () {/* 1) Important things three times: the go language does not contain encapsulation, inheritance, polymorphism, and other concepts, however, these features are also implemented in other ways. encapsulation: implemented through methods; inheritance: implemented through anonymous fields; polymorphism: implemented through interfaces 2) if all the members of the struct can be compared, the struct can also be compared, in this case, the two structs can use = or! = Operator, but not supported> or <. 3) * // 1) initialize the sequence. VaR S1 student = student {1, "ck_god", 0, 27, "SZ"} S2: = student {2, "god_girl", 1, 23, "SZ"} // S3: = student {3, "Stranger", "M", 20, "SZ"} // returns an error. The gender is byte, only 0 or 1 // S4: = student {3, "stranger0", 1, 20} // returns an error. Initialization is not specified. Each member must be initialized. // FMT. printf (S1, S2) // error, non-string type cannot print FMT. println (S1, S2) // println can access FMT. printf ("% T, % t", S1, S2) FMT. println ("") FMT. printf ("% v, % v", S1, S2) // 2) specifies that the member initializes FMT. println ("") S5: = student {ID: 2, name: "laowang"} // The uninitialized member is zero // s5.id, if student. ID: an error is returned. --- there is no ID for this method // 3) access the struct member variable FMT. printf ("ID = % d, name = % s, sex = % C, age = % d, ADDR = % s", s5.id, s5.name, s5.sex, s5.age, s5.addr) // 4) pointer variable FMT of struct. println ("") var S8 * student = & Student {8, "wck", 1, 20, "SZ"} S9: = & Student {9, "god_god ", 0, 21, "SZ"} FMT. printf ("% v, % v", S8, S9) // 5) Assign the value of the struct member variable to FMT. println ("") var S10 student S10.id = 2 s10.name = "Haha" s10.sex = 0 FMT. println (S10) // 6) ========================== the struct variable is the pointer variable S11: = new (student) s11.id = 11 s11.name = "www" FMT. println (S11) // 7) Common variables and pointer variable types print var S12 student = student {4, "mmm", 1, 20, "sh"} FMT. printf ("S12 = % v, & S12 = % V \ n", S12, & S12) // 8) two methods for obtaining members: var p * student = & S12 // P. member and (* P ). member operations are equivalent to P. id = 15 (* P ). name = "Zzz" FMT. println (p, * P, S12) // 9) the struct is passed as the value of the function parameter VaR S13 student = student {1, "shenzhenbei", 1, 18, "SZ"} printstudentvalue (S13) // pass the value. Modifications to the form parameter do not affect the object FMT. println ("Main S =", S13) // 10) the struct is passed as a reference to the function parameter printstudentpointer (& S13) FMT. println ("Main S =", S13) // 11) Visibility of struct members, as described in the document header .} Func printstudentpointer (p * student) {P. ID = 250 FMT. println ("printstudentpointer P =", P )}

The output result is as follows:

{1 ck_god 0 27 SZ} {2 god_girl 1 23 SZ} Main. student, Main. student {1 ck_god 0 27 SZ}, {2 god_girl 1 23 SZ} id = 2, name = laowang, sex = & {8 wck 1 20 SZ }, & {9 god_god 0 21 SZ} {2 Haha 0 0} & {11 www 0 0} S12 = {4 Mmm 1 20 sh }, & S12 = & {4 Mmm 1 20 sh} & {15 ZZZ 1 20 sh} {15 ZZZ 1 20 sh} {15 ZZZ 1 20 sh}

The initial experience of "class" struct in go