use of cin.ignore()

[NPcomplete]

i want to know about the function std::cin.ignore() and where it can be used. thank you.

[giblit]

You can use it to ignore unwanted things in the buffer.

http://www.cplusplus.com/reference/istream/istream/ignore/?kw=cin.ignore

std::istream::ignore
istream& ignore (streamsize n = 1, int delim = EOF);
Extract and discard characters
Extracts characters from the input sequence and discards them, until either n characters have been extracted, or one compares equal to delim.

The function also stops extracting characters if the end-of-file is reached. If this is reached prematurely (before either extracting n characters or finding delim), the function sets the eofbit flag.

Internally, the function accesses the input sequence by first constructing a sentry object (with noskipws set to true). Then (if good), it extracts characters from its associated stream buffer object as if calling its member functions sbumpc or sgetc, and finally destroys the sentry object before returning.

Parameters
n
Maximum number of characters to extract (and ignore).
If this is exactly numeric_limits<streamsize>::max(), there is no limit: As many characters are extracted as needed until delim (or the end-of-file) is found.
streamsize is a signed integral type.
delim
Delimiting character: The function stops extracting characters as soon as an extracted character compares equal to this.
If this is the end-of-file value (EOF), no character will compare equal, and thus exactly n characters will be discarded (unless the function fails or the end-of-file is reached).

[NPcomplete]

can you please tell me how ignore() is working in this program::

#include <iostream>
const int Limit = 255;
int main()
{
using std::cout;
using std::cin;
using std::endl;
char input[Limit];
cout << "Enter a string for getline() processing:\n";
cin.getline(input, Limit, '#');
cout << "Here is your input:\n";
cout << input << "\nDone with phase 1\n";
char ch;
cin.get(ch);
cout << "The next input character is " << ch << endl;
if (ch != '\n')
cin.ignore(Limit, '\n'); 
cout << "Enter a string for get() processing:\n";
cin.get(input, Limit, '#');
cout << "Here is your input:\n";
cout << input << "\nDone with phase 2\n";
cin.get(ch);
cout << "The next input character is " << ch << endl;
return 0;
}