ExempleTemplateInteger

<source lang="c++">

1. include <iostream>
2. include <sstream>
3. include <string>
4. include <gmp.h>

using namespace std;

class Integer {

 mpz_t m_v;

public:

 ~Integer()
 {
   cout << "~Integer( )" << endl;
   mpz_clear( m_v );
 }
 Integer()
 {
   cout << "Integer( )" << endl;
   mpz_init( m_v );
 }
 Integer( int x )
 {
   cout << "Integer( int )" << endl;
   mpz_init_set_si( m_v, x );
 }
 Integer( const Integer & other )
 {
   cout << "Integer( Integer & )" << endl;
   mpz_init_set( m_v, other.m_v );
 }
 Integer operator*( const Integer & other ) const
 {
   cout << "Integer Integer::operator*( Integer & )" << endl;
   Integer i;
   mpz_mul( i.m_v, m_v, other.m_v );
   return i;
 }
 void selfDisplay( ostream & that_stream ) const
 {
   char s[ 1000 ];
   mpz_get_str( s, 10, m_v );
   that_stream << s;
 }

};

ostream & operator<<( ostream & that_stream, const Integer & object ) {

 object.selfDisplay( that_stream );
 return that_stream;

}

template <typename Tint> Tint multiply( const Tint & a, const Tint & b ) {

 Tint t = a * b;
 cout << "[" << sizeof( Tint ) << "]" 
      << endl;
 cout << a << "*" << b << "=" << t << endl;
 return t;

}

int main( int argc, char** argv ) {

 Integer a( 987654321 );
 Integer b( 123456789 );
 int c = multiply( 5, 12 );
 int d = multiply( 17LL, 18LL );
 Integer e = multiply( a, b );
 Integer f = multiply( e, e );

} </source>