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tellp() in file handling with c++ with example

  • Difficulty Level : Medium
  • Last Updated : 12 Jul, 2021

The tellp() function is used with output streams, and returns the current “put” position of the pointer in the stream. It has no parameters and return a value of the member type pos_type, which is an integer data type representing the current position of the put stream pointer.
Syntax: 
 

pos_type tellp();

Return – Current output position indicator on success otherwise  return -1.
Example 1 – 
 

CPP




// cpp code to get the position at particular
// position using tellp() function
#include <iostream>
#include <fstream>
using namespace std;
 
int main()
{
    fstream file;
 
    // open file in read and write mode
    file.open("myfile.txt", ios::out);
    file << "geeksforgeeks";
 
    // print the position of the pointer in file
    cout << "the current position of pointer is :"
         << file.tellp() << endl;
 
    // close the open file
    file.close();
}

Output – 
 

the current position of pointer is :-1

In the above code the tellp() returns the current position to which it point in a file.
Example 2 – 
 



CPP




// code to add content at particular position
// using tellp()
#include <fstream>
using namespace std;
 
int main()
{
    long position;
    fstream file;
 
    // open the file in read and write mode
    file.open("myfile.txt");
 
    // write content in the file
    file.write("this is an apple", 16);
    position = file.tellp();
 
    // set position of pointer using seekp
    file.seekp(position - 7);
    file.write(" sam", 4);
    file.close();
}

Output – 
 

this is a sample

Here tellp() function returns the position of pointer then using seekp() function the pointer is shift back from n position here it shift 7 position back and then insert the content at that position .
This article is contributed by Shivani Baghel . If you like GeeksforGeeks and would like to contribute, you can also write an article using write.geeksforgeeks.org or mail your article to review-team@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.
 

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