// String
#include <iostream>
using namespace std;
class str{
    string s;
    public:
    void set(string x){
        s=x;
    }
    void display(){
        cout<<s<<endl;
    }
    void operator+(str &A){
        s.append(A.s);
    }
    void operator=(str &A){
        s=A.s;
    }
    bool operator<=(str &A){
        if(s.length()<A.s.length()){
          return true;  
        }
        return false;
    }
    void len(){
        cout<<s.length()<<endl;
    }
    void to_up(){
        for(int i=0;i<s.length();i++){
            if(s[i]>='a' && s[i]<='z'){
                s[i]=s[i]-32;
            }
        }
    }
    void to_low(){
        for(int i=0;i<s.length();i++){
            if(s[i]>='A'&&s[i]<='Z'){
                s[i]=s[i]+32;
            }
        }
    }
};
int main() {
    str a,b,c,d;
    a.set("Helllo");
    b.set("Programmer");
    a+b;
    a.display();
    a.len();
    c.set("Welcome");
    d=c;
    d.display();
    cout<<(d<=a)<<endl;
    d.to_up();
    d.display();
    a.to_low();
    a.display();
    return 0;
}

// matrix multiplication
#include <iostream>  
using namespace std;  
int main()  
{  
int a[10][10],b[10][10],mul[10][10],r,c,i,j,k;    
cout<<"enter the number of row=";    
cin>>r;    
cout<<"enter the number of column=";    
cin>>c;    
cout<<"enter the first matrix element=\n";    
for(i=0;i<r;i++)    
{    
for(j=0;j<c;j++)    
{    
cin>>a[i][j];  
}    
}    
cout<<"enter the second matrix element=\n";    
for(i=0;i<r;i++)    
{    
for(j=0;j<c;j++)    
{    
cin>>b[i][j];    
}    
}    
cout<<"multiply of the matrix=\n";    
for(i=0;i<r;i++)    
{    
for(j=0;j<c;j++)    
{    
mul[i][j]=0;    
for(k=0;k<c;k++)    
{    
mul[i][j]+=a[i][k]*b[k][j];    
}    
}    
}    
//for printing result    
for(i=0;i<r;i++)    
{    
for(j=0;j<c;j++)    
{    
cout<<mul[i][j]<<" ";    
}    
cout<<"\n";    
}    
return 0;  
}   

// cylinder wala
#include<iostream>
using namespace std;
class Cylinder{
  float r,h;
  float Pi=3.14;
  public:
  float area();
  float vol();
  float s_area();
  float read(float,float);
  float show();
};
float Cylinder::area(){
  return 2*Pi*r*(r+h);
}
float Cylinder::vol(){
  return 2*Pi*r*r*h;
}
float Cylinder::s_area(){
  return 2*Pi*r*h;
}
float Cylinder::read(float r_in, float h_in){
  r=r_in;
  h=h_in;
}
void Cylinder::show(){
  cout<<"area"<<area();
  cout<<"vol"<<vol();
  cout<<"surface area"<<s_area();
}
int main(){
  Cylinder c;
  float r,h;
  cout<<"r"<<endl;
  cin>>r;
  cout<<"h"<<endl;
  cin>>h;
  c.read(r,h);
  c.show();
  return 0;
}

//maximum number using friend function
#include<iostream>
using namespace std;
class number2;
class number1
{
    float a;
    public:
    void getdata1()
    {
      cout<<"Enter value for first number:";
      cin>>a;
    }
    friend float max(number1,number2);
};
class number2
{
    float b;
    public:
    void getdata2()
    {
        cout<<"Enter value for second number:";
        cin>>b;
    }
    friend float max(number1,number2);
};
float max(number1 A, number2 B)
{
    if(A.a>B.b)
    return A.a;
    else return B.b;
}

int main()
{
number1 d;
number2 e;
d.getdata1();
e.getdata2();
cout<<"Greater of two numbers is: "<<max(d,e);
return 0;
}

//Addition of two complex number using constructor overloading
#include<iostream>
using namespace std;
class complex
{
    float real, imag;
    public:
    complex() { }
    complex(float a) {real=imag=a;}
    complex(float x, float y) {real=x; imag=y;}
    void sum(complex c1, complex c2){
    real=c1.real+c2.real;
    imag=c1.imag+c2.imag;
}
    void show()
{
    cout<<real<<"+"<<imag<<"i"<<endl;
}
};

int main(){
 float a, b, c ; 
 cout<<"Enter the values of a and b and c:"<<endl;
 cin>>a>>b>>c;
 complex c1(a);
 complex c2(b,c);
 c2.sum(c1,c2);
 c2.show();
return 0;
}

//multilevel inheritence
#include<iostream>
using namespace std;
class Student{
  protected:
  int roll;
  public:
  void getroll(int x){
    cout<<"enter roll"<<endl;
    cin>>x;
    roll=x;
  }
};
class Test: public Student{
  protected:
  float sub1,sub2,sub3;
  public:
  void getmarks(float a, float b, float c){
    cout<<"enter sub1"<<endl
    cin>>a;
    cout<<"enter sub2"<<endl
    cin>>b;
    cout<<"enter sub3"<<endl
    cin>>c;
    sub1=a;
    sub2=b;
    sub3=c;
  }
  void putmarks(){
    cout<<"marks are"<<sub1<<" "<<sub2<<" "<<sub3<<endl;
  }
};

class Result: public Test{
  float total;
  public:
  void setans(){
    total=sub1+sub2+sub3;
  }
  void show(){
    cout<<"totsl"<<total;
  }
};
int main(){
  Result R1;
  R1.getroll(10);
  R1.getmarks(100,100,100);
  R1.setans();
  R1.putmarks();
  R1.showtotal();
  retrun 0;
}

// multiply using class template
#include<iostream>
using namespace std;
template <class T>
class Calculate{
    private:
    T a;
    T b;
    public:
    Calculate(T a, T b);
        T add();
        T mul();
};

template<class T>
Calculate <T>::Calculate(T x, T y){
    a=x;
    b=y;
}
template<class T>
T Calculate<T>::add(){
    T c;
    c=a+b;
    return c;
}
template<class T>
T Calculate<T>::mul(){
    T c;
    c=a*b;
    return c;
}
int main(){
    Calculate<int> obj(10,5);
    cout<<obj.add()<<endl;
    cout<<obj.mul()<<endl;
}

// virtual
#include <iostream>
using namespace std;
class base{
    public :
        virtual void display(){
            cout << "base class" << endl;
}
};
class derived : public base
{
public:
    void display()
    {
        cout << "derived class" << endl;
    }
};
int main()
{
    derived d;
    base *b = &d;
    b -> display();
    return 0;
}