Hello,

currently i'm writing a program for my exams, and i happened upon a problem with cin. My program requies a login inputted by the user which is 20 chars long. I have written a function that cuts 20 first chars if user inputted more chars (to avoid buffer overflow), but i was wondering if it's possible to overload cin in a way that if user inserted 20 chars then no more is accepted and user is to correct inputted login or press enter.

Thanks in advance

//excuse my bad english in advance
//because I don't use it all the time
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Object oriented programming
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INPUT AND OUTPUT IN C++

INPUT
#include <iostream>
int main(){
int n; double d;
std::cin >> n >> d;
   return 0;
}

OUTPUT
#include <iostream>
int main(){
int n = 10;
std::cout << n << '*' << n << " je " << n*n;
   return 0;
}

MANIPULATORS:
ends (end of string)
endl (end of line)
flush (flushing the buffer)
setprecision (precision of real numbers)
setw (print width)
setbase (base of whole numbers 8, 10 or 16)
setfill (fill sign)
setiosflags (sets certain formats)(see: ios flags)
resetiosflags (resets given formats)(see: ios flags)

IOS FLAGS:
boolalpha (prints bool values as a string,else as number)
dec (decimal format for whole numbers)
fixed (floating point format for real numbers)
hex (hexadecimal fotmat for whole numbers)
internal (empty spaces between sign and number- or base mark)
left (left alignment)
oct (octal format for whole numbers)
right (right alignment)
scientific(exponential form for real numbers)
showbase (prefiks for base of a whole numbers)
showpoint (decimal point)
showpos (plus sign)
skipws (skipping whitespaces - spaces, tabs, ...)
unitbuf (buffer emptying after every input)
uppercase (upper letters A-F in heksadecimal view)

example:
#include <iostream>
#include <iomanip>
int main(){
double d = 123.456789;
std::cout << std::setiosflags(std::ios::scientific | std::ios::left);
std::cout << std::setprecision(9) << std::setw(20) << std::setfill('_');
std::cout << d << std::endl;
   return 0;
}
greetings from: CROATIA
posted by: icopec