raihan.cpp

/// For virtual Function
/// Code number 1:
#include <iostream>
using namespace std;
class A{
    int a;
 public:
     A(){a = 0;}
    virtual void dis(){cout<<a<<endl;}


};
class B: public A{
 int b;
 public:
     B(){b = 2;}
     void dis(){cout<< b << endl;}

};
int main()
{
  A *p;
  B x;

  p = &x;

  p->dis();


}
/// Code number 2
/// Pure virtual Function
#include <iostream>
using namespace std;
class A{
    int a;
 public:
     A(){a = 0;}
    virtual void dis()= 0;
};
class B: public A{
 int b;
 public:
     B(){b = 2;}
     void dis(){cout<< b << endl;}

};
int main()
{
  A *p;
  B x;
  p = &x;
  p->dis();
}
///Topix  File read
///Code Number
#include <iostream>
#include <fstream>
using namespace std;
int main()
{
    ifstream in("test.txt");

    char c;

    while(1)
    {
       in >> c;

        if(in.eof());

        break;

        cout<<c<<endl;
    }

    in.close();
}
/// Create a file and read
/// Constructor for inheritance
#include <iostream>
using namespace std;
class A
{
    int x;

public:
  A(int i){x = i;}

  void show() {cout<< x << endl;}
};

class B : public A{
  int y;
  public:
       B(int a , int l): A(l){y = a;}
      void dis(){cout<< y << endl;}

};
int main()
{
    A p(3);
    p.show();

}
/// Generic Function (Template)
Code 1
#include <iostream>
using namespace std;
template <class t>
t max1(t a , t b)
{
    if(a > b)
        return a;
    else
        return b;
}
int main()
{
    cout<< max1(1, 4) << endl;
    cout<< max1('c' , 'b')<< endl;
    cout<< max1(2.5 , 3.1)<< endl;
}
/// Generic class (template)
#include <iostream>
using namespace std;

template <class t>
class A
{
    t a;
public:
    A(){a  = 0;}
   void set(t k)
   {
       a = k;
   }
   void dis(){cout<< a << endl;}
};

int main()
{
    A <int> ob;
    ob.set(1);
    ob.dis();
    A <char> ob1;
    ob1.set('a');
    ob1.dis();
}
/// execption Handiling (Try , catch , Throw)
#include <iostream>
using namespace std;
int main()
{
    try{
        cout<< "try"<< endl;
      throw 1;
    }
    catch(int i)
    {
        cout<< "Catch " << i << endl;
    }
}
/// Virtual overrid (এই কোড টা ২ বার আসছে ) ট্রাইএঙ্গেল , রেক্ট্যেংল দিয়ে
#include <iostream>
using namespace std;
class figure
{
public:
    double a , b;
    figure(double x , double y){a = x , b = y;}
    virtual double dis() = 0;

};
class rectangle: public figure
{
public:
    rectangle(double x, double y): figure(x , y){};
    double dis(){return a * b;}
};
class triangle: public figure
{
public:
    triangle(double x , double y): figure(x , y){};
   double dis(){return a * b;}
};
int main()
{
   rectangle ob(2, 3);
   figure *a;
   a = &ob;
   cout<<a -> dis() << endl;
   triangle ob2(4 ,6);
   a = &ob2;

   cout<< a -> dis() << endl;
}