#include<iostream.h>
class Count
{
                friend void setX(Count &,int);    //friend function declaration
public:
                Count()
                {                              //constructor
                                x = 0;
                }
                void print()
                {
                        cout << x << endl;
                }

private:
                int x;                      //data member
};

//...etc

#include <fstream.h>
void main()
{
                char line[80];
                ifstream in("hai.txt",ios::nocreate);
                if(in.fail())
                {
                                cerr<<"Error opening file."<<endl;
                }
                else
                {
                                while(!in.eof())
                                {
                                                in.getline(line, sizeof(line));
                                               
                                                                cout<<line<<endl;
                                }             
                }
                in.close();
}

#include<iostream>
using namespace std;
void main()
{

                cout<<"Don't do that again!\a\n";
                cout<<"Ben \"Buggsie\" Hacker was here! \n";
                cout<<"Ben\tFranklin\n";
                cout<<"Lionel \bRitchie\n";
                cout<<"Tech"<<endl;
                cout<<"Car\'ib\n";
                cout<<"\"Why\\\\\n";
}

#include <fstream.h>
void main()
{
                ifstream input_file("STR.TST");
                char string[60];
               
                while(! input_file.eof())
                {
                                //input_file.getline(string,sizeof(string));//for fetching a line at a time
                                //cout << string<<endl;
                               
                                //input_file >> string; //for fetching a word at a time
                                //cout << string << endl;

                                char letter=input_file.get(); //for fetching one character at a time
                                cout<<letter<<" ";

                }
}

#include <iostream>
#include <string>
using namespace std;
class employee
{
     char name[30];
     char designation[30];

     public:
          employee(char *, char *);
          employee(const employee &);
          void Print(void);
  };
               
employee::employee(char * n,char *d)
{
         strcpy(name,n);
         strcpy(designation,d);
}

employee::employee(const employee & e)
{
        strcpy(name,e.name);
        strcpy(designation,e.designation);
}

void employee::Print()
{
        cout<<"Employee Name \t:"<<name<<"   Employee Designation\t:"<<designation<<endl;
}
void main()
{
        employee e("John Doe","Manager");
        employee e1(e);
        e.Print();
        e1.Print();
}

#include <fstream.h>
#include <string.h>

class Vehicle
{
public:
                int serialNo;
                char model[8];
                float price;
};

int main()
{
                ofstream out("OBJ.DAT");
                Vehicle car;
                car.serialNo=25;
                strcpy(car.model,"Dinky");
                car.price=1232.34f;
                out<<car.serialNo<<endl<<car.model<<endl<<car.price;
                //out.write((char *)&car,sizeof(Vehicle));
                return 0;
}

#include <fstream.h>

class Vehicle
{
public:
                int serialNo;
                char model[8];
                float price;
};

int main()
{
                ifstream in("OBJ.DAT");
                Vehicle car;
                in>>car.serialNo>>car.model>>car.price;
                cout<<car.serialNo<<endl<<car.model<<endl<<car.price<<endl;
                return 0;
}

#include<iostream.h>

class Count
{
public:
                Count(){   //constructor
                                x = 0;
                }

                 void cannotsetX(Count &c, int val);

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

private:
                int x;  //data member
};

//Function cannot alter data member because it
//is not a friend of Count

void cannotsetX(Count &c, int val)
{
                c.x = val;    //Count::x is not accessible
}

void main()
{
                Count counter;

                cout << "Counter.x after instantiation: ";
                counter.print();
                cout << "Counter.x after call to setX friend function: ";
                cannotsetX(counter,3); //cannotsetX is not a friend
                counter.print();
}

#include <iostream>
using namespace std;

class Fraction
{
public:
                Fraction (int num=0, int den=1)
                {
                                this->num=num;
                                this->den=den;
                }
                Fraction operator+(const Fraction &rhs)
                {
                                Fraction temp;
                                temp.den = this->den*rhs.den;
                                temp.num = rhs.den * this -> num + this->den * rhs.num;
                                return temp;
                }
                Fraction operator-(const Fraction &rhs)
                {
                                Fraction temp;
                                temp.den = this->den*rhs.den;
                                temp.num = rhs.den * this -> num - this->den * rhs.num;
                                return temp;
                }
                Fraction operator*(const Fraction &rhs)
                {
                                Fraction temp;
                                temp.den = this->den*rhs.den;
                                temp.num = this->num* rhs.num;
                                return temp;
                }
                Fraction operator/(const Fraction &rhs)
                {
                                Fraction temp;
                                temp.den = this->den*rhs.num;
                                temp.num = this->num*rhs.den;
                                return temp;
                }

                void print()
                {
                                cout<<num<<"/"<<den<<endl<<endl;
                }
                private:
                int num;
                int den;

};

//Call Main()

#include <iostream>
using namespace std;

template <class Type>
    void ConvertFToC(Type f, Type &c);

int main()
{
    double df, dc;
    float ff, fc;
    int inf,inc; //if is a reserved word

    df = 75.0;
    ff = 75.0;
    inf = 75;
    // The compiler instantiates a version of
    // ConvertFtoC based on the data types of
    // the arguments in the function invocations.
    ConvertFToC(df,dc);
    cout << df << " == " << dc << endl << endl;
    ConvertFToC(ff,fc);
    cout << ff << " == " << fc << endl << endl;
    ConvertFToC(inf,inc);
    cout << inf << " == " << inc << endl << endl;
                return 0;
}
template <class Type>
//Call Calculator

#include <iostream>
using namespace std;
void main()
{
                double d;
                cout<< "Type a value d:";
                cin >> d;
                double c;
                c=d*5+1;

                cout<<"c contains : "<<c<<endl;
                int i,j;
                i=3;
                j=i+1;
                cout<<"j contains : "<<j<<endl;
}