Non-Type Parameters For Template

Besides the template arguments that are preceded by the class or typename keywords , which represent types, templates can also have regular typed parameters, similar to those found in functions. As an example, have a look at this class template that is used to contain sequences of elements:

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// sequence template #include <iostream> using namespace std; template <class T, int N> class mysequence {     T memblock [N];   public:     void setmember (int x, T value);     T getmember (int x); }; template <class T, int N> void mysequence<T,N>::setmember (int x, T value) {   memblock[x]=value; } template <class T, int N> T mysequence<T,N>::getmember (int x) {   return memblock[x]; } int main () {   mysequence <int,5> myints;   mysequence <double,5> myfloats;   myints.setmember (0,100);   myfloats.setmember (3,3.1416);   cout << myints.getmember(0) << '\n';   cout << myfloats.getmember(3) << '\n';   return 0; }

100 3.1416

It is also possible to set default values or types for class template parameters. For example, if the previous class template definition had been:

template <class T=char, int N=10> class mysequence {..};

We could create objects using the default template parameters by declaring:

mysequence<> myseq;

Which would be equivalent to:

mysequence<char,10> myseq;