The document contains several C++ code snippets and functions that demonstrate reading from and writing to files using classes, structures, and other data types. Specifically: 1) It shows how to create a class to store telephone numbers and names, write objects of that class to a file, and read them back. 2) It contains functions that open, read from, and write to files while counting elements like words, lines, and characters within the files. 3) Operations demonstrated include copying files, extracting specific data like words starting with vowels, and converting case (such as uppercase).

1. #include<iostream.h>
#include<fstream.h>
#include<math.h>
void main()
{
clrscr();
ofstream fout("Myfile");
fout<<"Ganesh";
fout.close();
ifstream fin("Myfile");
char ch;
while(fin)
{
fin.get(ch);
cout<<ch;
}
fin.close();
getch();
}
52. Write a program that will create a data file containing the list of telephone numbers
and name. Use a class object to store each set of data.
/*
* To write the complex data types like array, structure or
* classes, we have already discussed that only one method
* for read and one method for write is used :
* These are - fout.write((char *)&obj, sizeof(obj));
* and fin.read((char *)&newObj, sizeof(newObj));
*/
#include<fstream.h>
#include<conio.h>

2. #include<iostream.h>
#include<fstream.h>
class tel
{
private:
char *name, *number;
public:
void setdata()
{
cout<<"Enter Name and number"<<endl;
cin>>name>>number;
}
void display()
{
cout<<"Name : "<<name<<endl;
cout<<"Number : "<<number<<endl;
}
};
void main()
{
tel obj;

3. obj.setdata();
obj.display();
ofstream fout;
fout.open("om.txt",ios::out);
fout.write((char *)&obj, sizeof(obj));
cout<<"successfully written on file: ";
fout.close();
ifstream fin;
tel newObj;
fin.open("om.txt",ios::in);
fin.read((char *)&newObj, sizeof(newObj));
cout<<" Read Succesfull"<<endl;
newObj.display();
getch();
}
#include <iostream.h>
#include <fstream.h>
/*
* Copy one file onto the end of another, adding line numbers
*/
int main () {
char myline[256];
int lc = 0;

4. ofstream outfile("demo.txt",ios::app);
ifstream infile("stdcodes.xyz");
if (! infile) {
cerr << "Failed to open input filen";
exit(1);
}
while (1) {
infile.getline(myline,256);
if (infile.eof()) break;
lc++;
outfile << lc << ": " << myline << "n";
}
infile.close();
outfile.close();
cout << "Output " << lc << " records" << endl;
}
/* Sample Output
munchkin:c235 grahamellis$ ./file01
Output 110 records
munchkin:c235 grahamellis$
*/
C++ program to write number 1 to 100 in a data file NOTES.TXT
#include<fstream.h>
int main()
{
ofstream fout;
fout.open("NOTES.TXT");
for(int i=1;i<=100;i++)
fout<<i<<endl;
fout.close();
return 0;
}

5. C++ program, which initializes a string variable and outputs the string to the disk file
#include<fstream.h>
int main()
{
ofstream fout;
fout.open("out.txt");
char str[300]="Time is a great teacher but unfortunately it kills
all its pupils. Berlioz";
fout<<str;
fout.close();
return 0;
}
User-defined function in C++ to read the content from a text file OUT.TXT, count and
display the number of alphabets present in it
void alphabets()
{
ifstream fin;
fin.open("out.txt");
char ch;
int count=0;
while(!fin.eof())
{
fin.get(ch);
if(isalpha(ch))
count++;
}
cout<<"Number of alphabets in file are "<<count;
fin.close();
}
User defined function in C++ to count the number of blank present in a text file named
"OUT.TXT".
void blankspace()
{
ifstream fin;

6. fin.open("out.txt");
char ch;
int count=0;
while(!fin.eof())
{
fin.get(ch);
if(ch==' ')
count++;
}
cout<<"Number of blank spaces in file are "<<count;
fin.close();
}
User defined function in C++ to print the count of word the as an independent word in a
text file STORY.TXT
void countword()
{
ifstream fin;
fin.open("STORY.TXT");
char word[30];
int count=0;
while(!fin.eof())
{
fin>>word;
if(strcmpi(word,"the")==0)
count++;
}
cout<<"Number of the word in file are "<<count;
fin.close();
}
Function in C++ to count and display the number of lines not starting with alphabet 'A'
present in a text file "STORY.TXT"
void countlines()
{
ifstream fin;
fin.open("STORY.TXT");
char str[80];
int count=0;
while(!fin.eof())
{
fin.getline(str,80);
if(str[0]!='A')

7. count++;
}
cout<<"Number of lines not starting with A are "<<count;
fin.close();
}
User defined function in C++ named copyupper(), that reads the file FIRST.TXT and
creates a new file named SECOND.TXT contains all words from the file FIRST.TXT in
uppercase
void copyupper()
{
ifstream fin;
fin.open("FIRST.TXT");
ofstream fout;
fout.open("SECOND.TXT");
char ch;
while(!fin.eof())
{
fin.get(ch);
ch=toupper(ch);
fout<<ch;
}
fin.close();
fout.close();
}
A C++ function, that reads the file FIRST.TXT and creates a new file named
SECOND.TXT, to contain only those words from the file FIRST.TXT which start with a
lowercase vowel
void vowelwords()
{
ifstream fin;
fin.open("FIRST.TXT");
ofstream fout;
fout.open("SECOND.TXT");
char word[30];
while(!fin.eof())
{
fin>>word;
if(word[0]=='a'||word[0]=='e'||word[0]=='i'||word[0]=='o'||word[0]=='u
')

8. fout<<word<<" ";
}
fin.close();
fout.close();
}
ser defined function in C++ to count number of words in a text file named "OUT.TXT"
void countwords()
{
ifstream fin;
fin.open("out.txt");
char word[30];
int count=0;
while(!fin.eof())
{
fin>>word;
count++;
}
cout<<"Number of words in file are "<<count;
fin.close();
}