12 and 12.5

[AbhijitRaj]

Hello everyone!
I am new to this programming world.
I recently wrote a program that prints the sum of the series 1 + 1/2 + 1/3 +...+1/n.

It works perfectly for integers, but how do i get it to say display an error message when someone enters a floating point number.
Right now my program treats 12.5 as 12 and prints the output.

Thanks!

[hamsterman]

You must have declared some variable int rather than float or double.
Post the code, if you didn't find the problem already.

[Zhuge]

If you are cin>>ing into a int, it will stop at the radix point as that isn't a valid number. You would have to read all the data in as, say, a string, then check to see if there are any invalid characters. You could also read the data then check to see if there is anything other than a newline left, and if so, complain.

[Duthomhas]

I prefer the latter.

Here's an improved version of an answer I gave 1 1/2 months ago... (This is the first method...)

cout << "Please enter an integer in the range [19, 37]: " << flush;
int n;
while (true)
  {
  cin >> n;

  if ((cin) && (n >= 19) && (n <= 37))
    break;

  cin.clear();
  cin.ignore( 1000, '\n' );
  cout << "Hey, follow instructions please: " << flush;
  }
cin.ignore( 1000, '\n' );
cout << "Good job!\nYou entered the number '" << n << "'.\n";

There is also this (which is my prefered method):
http://www.cplusplus.com/forum/beginner/13044/page1.html#msg62827

:-)