A preliminary study of C + + class template Learning Notes

Class template

Implementation: When defining a class, give it one or more of the parameters, which represent different data types. --abstract class.

When a class template is called, the specified number of parameters is generated by the data type provided by the compilation system itself, and the corresponding template class---the detailed class.

Definition of a class template

The C + + class template is written such as the following:

Template < Type tables >        //Type tables are written as follows: Class type 1, class Type 2, ... class template name {    member function and member variable};

A member function in a class template, as defined outside the class template,

Template < Type table > return value type class templates name < type parameter name list;:: member function name (parameter) {     ...}

Use a class template to define an object's wording such as the following:
Class template Name < real type Reference > object name (constructor actual tables);
Assuming that the class template has no constructor, it can also simply write:
Class template name < real type tables > object names;

Example:

Template <class T1, class T2>class pair{public:    T1 key;  Keyword    T2 value;  Value    Pair (T1 k,t2 v): Key (k), value (v) {};    BOOL operator < (const pair<t1,t2> & P) const; };template<class t1,class t2>    //The member function that defines a Pair outside the class operator <bool pair<t1,t2>::operator< (const PAIR<T1, T2> & P) Const {return key < P.key;}  

Use of the pair class template:

int main () {    pair<string, int> student ("Tom", +);     Instantiate a class pair<string, int>    cout << student.key << "" << Student.value;     return 0;}

function templates as class template members

#include <iostream>using namespace Std;template <class t>class a{public:    template<class T2>     void Func (T2 t) {cout << t;}//member function template};int main () {    a<int> A;    A.func (' K '); The member function template func is instantiated with     return 0;}

Class templates and non-type parameters

Template <class T, int size>class carray{    t array[size];p ublic:    void Print ()     {for        (int i = 0; I &l T Size ++i)        cout << array[i] << Endl;     }       ;

Carray<double, 40> A2; Carray<int, 50> A3;

Note:
Carray<int,40> and carray<int,50> are totally two classes.
The objects of these two classes cannot be assigned to one another

Class templates and inheritance

Generic classes derive from template classes

Template <class t>class A {T v1;  int n; };class b:public a<int> {double v;  };/ /Class A is a class template,a<int> is a template class int main () {     B obj1;     return 0;}

Class templates derive from template classes

Template <class T1, class T2>class A {T1 v1; T2 v2;    }; Template <class t>class b:public  a<int, double> {T v;}; int main () {     b<char> obj1; return 0;}

Class template A, instantiation template class a<int,double>, derived class template B, instantiation template class b<char>

There are members in B at this time

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int v1;

Double v2;

T v;

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Class templates derive from ordinary classes

Class A {  int v1;}; Template <class t>class b:public A  {T v;}; int main () {     b<char> obj1;     return 0; }

There's nothing to say. A member of type T was added on the basis of inheriting a.

Class templates derive from class templates

#include <iostream>using namespace Std;template <class T1, class T2>class a{public:    T1 v1; T2 v2;}; Template <class T1, class T2>class b:public a<t1,t2>{public:    T1 v3; T2 v4;}; int main () {    b<int,double> B;    b<int,double> *PB = &b;    B.V1 = 1;    B.v3 = 3;    B.v2 = 2.2;    B.V4 = 4.4;    cout << pb->v1<<endl;    cout << pb->v2<<endl;    cout << pb->v3<<endl;    cout << pb->v4<<endl;    return 0;}

Make sure that class template A is instantiated with the type T as it is instantiated for class template B.

B<int,double> B. B has its own member int v3, double v4 also have members that inherit a<int,double> int v1 and double v2

A preliminary study of C + + class template Learning Notes