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1、Templates定义一个模板使用的关键字：class 和 typename。在定义作为模板的时候：class 和 typename，作用是一样的。一 函数模板1 定义方式template function_declaration;template function_declaration;2 Exampletemplate T GetMax (T a, T b) T result;result = (ab)? a : b;return (result);3 使用方法function_name (parameters);int x,y;GetMax (x,y);对于内部类型，通常是可以无需制定
2、具体的类型，编译器会自动识别，而是写成：int x,y;GetMax(x,y); /x，y 为相同的类型int x;long y;GetMax(x,y); /x，y 为不相同的类型 报错 两种不同的内部类型必须：template T GetMin (T a, U b) return (a (j,l); /或者 i = GetMin (j,l);二 Class Template通常是使用模板作为类成员变量的类型1 Example：template class mypair T values 2;public:mypair (T first, T second) /内联函数values0=firs
3、t; values1=second;mypair myobject (115, 36); /这样使用mypair myfloats (3.0, 2.18);2 成员函数为非内联函数template class mypair T a, b;public:mypair (T first, T second)a=first; b=second;T getmax ();template /增加此声明T mypair:getmax ()T retval;retval = ab? a : b;return retval;int main () mypair myobject (100, 75);cout
4、T mypair:getmax ()三 模板特化 Template Specialization1 将模板类转化为特定类型相关的类/ class template:template class mycontainer T element;public:mycontainer (T arg) element=arg;T increase () return +element;/ class template specialization:template /将其特例化为 char 型char element;public:mycontainer (char arg) element=arg;ch
5、ar uppercase ()if (element=a)&(element myint (7);mycontainer mychar (j);cout class mycontainer . ; /模板类template . ; /特例化为 char 型template . ; /特例化为 int 型模板来与之相应的特例化的类之间，并不是什么继承关系，所以在特例化一个模板类时，需要将其所有的包含成员进行重写，可以进行扩展。2 非模板类型参数 Non-type parameters for templatestemplate /int Nclass mysequence T memblock
6、N;public:void setmember (int x, T value);T getmember (int x);template void mysequence:setmember (int x, T value) memblockx=value;template T mysequence:getmember (int x)return memblockx;int main () mysequence myints;mysequence myfloats;myints.setmember (0,100);myfloats.setmember (3,3.1416);cout class
7、 mysequence .;mysequence myseq; /等同于上面四 Templates and multiple-file projectsFrom the point of view of the compiler, templates are not normal functions or classes. They are compiled on demand, meaning that the code of a template function is not compiled until an instantiation with specific template a
8、rguments is required. At that moment, when an instantiation is required, the compiler generates a function specifically for those arguments from the template.模板不会在代码编译的时候直接进行编译，而是在被实例化一个特定类型的模板时候，才会编译到，生成一个特定参数的函数。When projects grow it is usual to split the code of a program in different source code
9、 files. In these cases, the interface and implementation are generally separated. Taking a library of functions as example, the interface generally consists of declarations of the prototypes of all the functions that can be called. These are generally declared in a header file with a .h extension, a
10、nd the implementation (the definition of these functions) is in an independent file with c+ code.Because templates are compiled when required, this forces a restriction for multi-file projects: the implementation (definition) of a template class or function must be in the same file as its declaratio
11、n. That means that we cannot separate the interface in a separate header file, and that we must include both interface and implementation in any file that uses the templates.由于模板特殊的编译需要，模板类的定义和函数实现必须在同一个文件中进行。Since no code is generated until a template is instantiated when required, compilers are pr
12、epared to allow the inclusion more than once of the same template file with both declarations and definitions in a project without generating linkage errors.二 typename定义一个模板使用的关键字：class 和 typename。在定义作为模板的时候：class 和 typename，作用是一样的。使用 typename，实际上也是为模板服务的，在某些情况下我们需要明确的指出某些变量为模板。1 在一个模板类中使用另一个模板类定义一个
13、变量时templatestruct first typedef T * pointer;templateclass second first:pointer p; / syntax error （VC+中 并不报错）;In a template, the name of a member of another class that depends on its template parameter(s) (first:pointer in this example, dependent on the T parameter) is a dependent name that is not looked-up immediately. To tell the compiler that it is meant to refer to a type and not some other sort of member, you must add the keyword typename before it.（英文太烂，就不翻译了）typename 能够在：依赖类型中， typename 用来声明一个依赖于另一个模板类参数的嵌套类型。
