tellg() function in C++ with example
The tellg() function is used with input streams, and returns the current “get” position of the pointer in the stream. It has no parameters and returns a value of the member type pos_type, which is an integer data type representing the current position of the get stream pointer.
Syntax:-
pos_type tellg();
Returns: The current position of the get pointer on success, pos_type(-1) on failure.
Example 1
// C++ program to demonstrate // example of tellg() function. #include <bits/stdc++.h> using namespace std; int main() { string str = "w3wiki"; istringstream in(str); string word; in >> word; cout << "After reading the word \"" << word << "\" tellg() returns " << in.tellg() << '\n'; } |
Output:
After reading the word "w3wiki" tellg() returns -1
Example 2 :
// C++ program to demonstrate // example of tellg() function. #include <bits/stdc++.h> using namespace std; int main() { string str = "Hello, GFG"; istringstream in(str); string word; in >> word; cout << "After reading the word \"" << word << "\" tellg() returns " << in.tellg() << '\n'; } |
Output:
After reading the word "Hello," tellg() returns 6
Properties:-
tellg() does not report the size of the file, nor the offset from the beginning in bytes. It reports a token value which can later be used to seek to the same place, and nothing more. (It’s not even guaranteed that you can convert the type to an integral type)