How to make generic this function in C++ (i.e., template based) -

i use gcc version 4.6.3. want implement function allocate 2-dimensional matrices , initialize them. used following code, want template based (or generic) one. want generic function handle bool, float, , double @ same time (the procedure similar in cases). please me, or introduce me better way allocate 2d matrix.

void doublealloc2d(double ** &t, int r, int c,double initialvalue=0) {     t=new double*[r];     if (!t)     {         if (details) std::printf  ("not enough memory.(code: 461546596551)\n");         getchar();         exit(-1);     }      (int i=0;i<r;i++)     {         t[i] = new double[c];         if (!t[i])         {             if (details) std::printf  ("not enough memory.(code: 461651651)\n");             getchar();             exit(-1);         }         (int j=0;j<c;j++)             t[i][j] = initialvalue;     }  } 

you don't specify want generic, i'll guess type (and maybe dimensions). usual way create object (including containers, generic or not) in c++ define class. like:

template <typename t, int rows, int columns> class matrix {     std::vector<t> mydata; public:     matrix( t const& init = t() )         : mydata( rows * columns, init )     {     }     t* operator[]( int index )     {         return &mydata[0] + index * columns;     }     t const* operator[]( int index ) const     {         return &mydata[0] + index * columns;     }     //  ... }; 

if don't want rows , columns compile time constants, drop them template parameters, , add them constructor parameters. , don't forget save them.

a more complex (but still not difficult) solution use proxy class return value of operator[], rather t*. frequent solution override operator()( int i, int j ) indexing, , use m( i, j ) syntax, rather m[i][j].

there never cause use array new in c++. c++ not c, , shouldn't try program if were.