c++ - What does clearing of input buffer mean? -

i going through code in school textbook, wherein there line who's function clear input buffer (mentioned comment in code).

i couldn't quite understand purpose. required removal messes console input process.

please explain function is, , happening when remove it.

i have tried using cin.ignore(); , works fine too. how function used here, exact replacement of cin.ignore()?

p.s. in school using older version of c++. hence ".h" extension, clrscr();, etc.

#include <iostream.h> #include <fstream.h> #include <conio.h>  void main(){ clrscr();  ofstream fout("student.txt", ios::out); char name[30], ch; float marks = 0.0;  for(int = 0; < 5; i++){     cout << "student " << (i+1) << ":\tname: ";     cin.get(name,30);     cout << "\t\tmarks: ";     cin >> marks;     cin.get(ch);  //for clearing input buffer (this thing!)     fout << name << '\n' << marks << '\n'; }  fout.close();  ifstream fin("student.txt", ios::in); fin.seekg(0); cout << "\n";  for(int = 0; < 5; i++){     fin.get(name,30);     fin.get(ch); //again     fin >> marks;     fin.get(ch); //same     cout << "student name: " << name;     cout << "\tmarks: " << marks << "\n"; }  fin.close(); getch();  } 

cin >> marks; cin.get(ch);  //for clearing input buffer (this thing!) 

this not-so-robust way of clearing input buffer. if type number followed enter, first line consume number , put value in marks while second line read newline character , discard it.

it not robust since not account spaces user might have entered after number. more robust method use istream::ignore.

cin >> marks; cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');