Seekg() , Tellg() , Seekp() , Seekg()

C++ Examples#1

#include <iostream.h>
#include <fstream.h>

int main()
{
  ofstream fout;
	int i; char ch;
	// File opening in  output mode both
	fout.open("d:/test.txt",ios::in);
	if(!fout)
	{
		cout<<"Error in creating file..\n"; return 0;
	}
	// Writting A-Z in file.
	for(i=0;i<26;i++){
		fout.put((char)(65+i));
	}
	cout<<"Total bytes are : "<< fout.tellp() << endl;
	fout.close();
	// reading file ..

	ifstream fin;
	fin.open("d:/test.txt",ios::in);
	if(!fin)
	{
		cout<<"Error in opening file..\n"; return 0;
	}
	
	cout<<"\nCASE-1:\nFile's get pointer is in " << fin.tellg() <<" Position. \n";
	cout<<"Characters are ... :\n";
	while(!fin.eof()){
		fin.get(ch);
		cout<< ch;
	}

	// sets the get pointer to 10th byte 
	fin.clear(); // reset flags 
	fin.seekg(10,ios::beg);
	cout<<"\n\nCASE-2:\nFile's get pointer is in " << fin.tellg() <<" Position. \n";
	cout<<"Characters are ... :\n";
	while(!fin.eof()){
		fin.get(ch);
		cout<< ch;
	}

	// sets the get pointer to -20 bytes back
	fin.clear(); // reset flags 
	fin.seekg(-20,ios::cur);
	cout<<"\n\nCASE-2:\nFile's get pointer is in " << fin.tellg() <<" Position. \n";
	cout<<"Characters are ... :\n";
	while(!fin.eof()){
		fin.get(ch);
		cout<< ch;
	}
	cout<< endl;
	return 1;
}