Exercise I Can't Solve!

#include <iostream>
#include <cstdlib>
#include <ctime>

class matrix{
    public:
    matrix(int riga, int colonna){
        this->riga=riga;
        this->colonna=colonna;
    }
    matrix(){
        this->riga=0;
        this->colonna=0;
    }

    template <typename T> T crea(){
        auto a = new<T>*(riga);

        for(int i=0; i!=riga; ++i){
            a[i]=new<T>(colonna);
        }
    }

    private:
        int riga, colonna;
}
using namespace std;

int main(){
    auto v=crea<int>(5,10);
    srand(time(nullptr));


    for(int i=0, j=0; i!=5, j!=10; ++i, ++j){
        v[i][j]=rand()%100+1;
    }

    for(int i=0, j=0; i!=5, j!=10; ++i, ++j){
        cout<<v[i][j]<<endl;
    }
return 0;
}

m.cpp: In member function ‘T matrix::crea()’:
m.cpp:17:15: error: expected type-specifier before ‘<’ token
   auto a = new<t>*(riga);
               ^
m.cpp:17:17: error: expected primary-expression before ‘>’ token
   auto a = new<t>*(riga);
                 ^
m.cpp:17:24: error: invalid type argument of unary ‘*’ (have ‘int’)
   auto a = new<t>*(riga);
                        ^
m.cpp:20:12: error: expected type-specifier before ‘<’ token
    a[i]=new<t>(colonna);
            ^
m.cpp:20:14: error: expected primary-expression before ‘>’ token
    a[i]=new<t>(colonna);
              ^
m.cpp: In function ‘int main()’:
m.cpp:31:9: error: ‘crea’ was not declared in this scope
  auto v=crea<int>(5,10);
         ^
m.cpp:31:14: error: expected primary-expression before ‘int’
  auto v=crea<int>(5,10);

#include <iostream>
#include <cstdlib>
#include <ctime>

class matrix{
	public:
	matrix(){
		this->riga=0;
		this->colonna=0;
	}
	~matrix(){
	}
	template <typename T> T crea(){
		auto a = new T*[riga];

		for(int i=0; i!=riga; ++i){
			a[i]=new T[colonna];
		}
		return a;
	}
	
	private:
		int riga, colonna;
};

using namespace std;

int main(){
	matrix c;
	auto v=c.crea<int>();
	srand(time(nullptr));

	for(auto i=0, j=0; i!=5, j!=10; ++i, ++j){
		v[i][j]=rand()%100+1;
	}

	for(auto i=0, j=0; i!=5, j!=10; ++i, ++j){
		cout<<v[i][j]<<endl;
	}
return 0;
}

m.cpp: In function ‘int main()’:
m.cpp:34:6: error: invalid types ‘int[int]’ for array subscript
   v[i][j]=rand()%100+1;
      ^
m.cpp:38:12: error: invalid types ‘int[int]’ for array subscript
   cout<<v[i][j]<<endl;
            ^
m.cpp: In instantiation of ‘T matrix::crea() [with T = int]’:
m.cpp:30:21:   required from here
m.cpp:19:10: error: invalid conversion from ‘int**’ to ‘int’ [-fpermissive]
   return a;
          ^