File input & output pro C++

File I/O: Writing to a text file

#include 

#include

#include 

using namespace std;

int main()

{

   char outFile[80]; 

   ofstream outstream;  

   cout << "Please enter output file name: " ;

   cin >> outFile;

   outstream.open(outfile, ios::out | ios::trunc);

   if(!outstream)

   {

               cout << "Error open file " << outFile << " for writing\n";

               return 1;

   }

   outstream<<"It is easier to resist at the beginning than at the end.\n";

   outstream <<"                 -- Leonardo da Vinci" << endl;

   outstream.close(); 

   cout << "Content written to " << outFile <<".\n";

   return 0;

}

File I/O: Reading from a text file

#include 

#include

#include 

using namespace std;

int main()

{

   char inFile[80];  

   char ch;

   ifstream instream;

   cout << "This program reads the content of a file and ";

   cout << "prints it out on the screen." << endl;

   cout << "Enter input file name: " ;

   cin >> inFile;

   instream.open(inFile, ios::in);

   if(!instream)

   {

               cout << "Error open file " << inFile << endl;

               return 1;

   }

   cout << "Here is the content of " << inFile << ":\n";

   while (!instream.eof()) 

  {

               instream.get(ch);    

               if (!instream.eof()) 

               {

                           cout << ch;  

               }

   }

   instream.close();

}

A simple program demonstrating structure

#include 

#include

using namespace std;

int main()

{

        struct personaldata

        {

                char *firstname;

                char *lastname;

                char *birthday;  

                int  phonenum;

        }; 

        personaldata personone;

        personone.firstname = "john";

        personone.lastname = "doe";

        personone.birthday = "12/30/1978";

        personone.phonenum = 5855555;

        cout << "personone's first name is: " << personone.firstname << endl;

        cout << "personone's last name is: " << personone.lastname<< endl;

        cout << "personone's birthday is: " << personone.birthday<< endl;

        cout <<"personone's phone number is:"<

       return 0;

}

Nested structure

#include 

#include

using namespace std;

int main()

{

          struct name

        {

                char *firstname;

                char *lastname;

        };

        struct personaldata

        {

                name namefield; 

                char *birthday;  

                int  phonenum;

        }; 

        personaldata personone;

        personone.namefield.firstname = "John";

        personone.namefield.lastname = "Doe";

        personone.birthday = "12/30/1978";

        personone.phonenum = 5855555;

        cout << "First name is: " << personone.namefield.firstname << endl;

        cout << "Last name is: " << personone.namefield.lastname<< endl;

        cout << "Birthday is: " << personone.birthday<< endl;

        cout << "Phone number is: " << personone.phonenum<< endl;

        return 0;

}

Using functions in structure

#include 

#include

using namespace std;

int main()

{

         struct personaldata

        {

                char *firstName;

                char *lastName;

                char *birthday;  

                int  phonenum;

                void printdat()

                {

                        cout << "First name is: " << firstname << endl;

                        cout << "Last name is: " << lastname << endl;

                        cout << "Birthday is: " << birthday << endl;

                        cout << "Phone number is: " << phonenum << endl;

                }

        }; 

        personaldata personone;

        personone.firstname = "john";

        personone.lastname = "doe";

        personone.birthday = "12/30/1978";

        personone.phonenum = 5855555;

        personone.printdat();

        return 0;

}