Program is skipping cin.getline call

[rarmknecht]

I'm not quite sure what is happening here, just that after much cutting of code I am still able to recreate the error and have narrowed it down to this section.

If I remove the part where it asks for encryption/decryption it allows user input. However, if it that portion is included, it skips over the cin.getline(input, MAXLN); call and displays all the cout's as if input was blank. Any ideas? I'm compiling under linux but you can feel free to compile it under windows. It really doesn't matter to me.

And the code:

#include <iostream>
using namespace std;

const int MAXLN = 128;
bool encrypted;

int main(int argc, char * argv[])
{

		char input[MAXLN];	//Holdind the string
		char temp;


		cout << "Press 1 to encrypt.  Press 2 to decrypt.\n";
		cin >> temp;

		if(temp == '2')	//Decryption needed
		{
			encrypted = true;
			cout << "Decryption it is then!" << endl;
		}
		else
		{
			if(temp == '1')
			{
				encrypted = false;
				cout << "Encryption is it then!" << endl;
			}
			else
			{
				cout << "You should have entered a number!" << endl;
				return 1;
			}
		}
	
		
		cout << "\nPlease enter in the text you would like to modify:" << endl;

		//grab the input string
		cin.getline(input, MAXLN);
		
		cout << "You entered: " << input << endl;
		
		return 0;
}

[joe_bruin]

you are not handling user input correctly. you ask the user to enter 1 or 2. really, the user presses 1, and presses the enter key. so now there are two bytes in the input buffer, "1\n". your cin >> temp eats the '1', but the '\n' is still sitting in the input buffer.
when you call cin.getline(input, MAXLN);, it gets the next line from the input buffer (ie, the "\n" that was waiting for it there), and it's done.

[Valmont]

Hi, I noticed you wish to work in the standard namespace, yet you use cin.getline().
Use getline().
Here is a nice piece of code to validate correct input. You can change the int to anyting like a bool in your case.

  //uses <strstream>
  string sInLine;
  bool bValid = false;
  bool bNonDigit = false;
  int  nNumber;
  
  while( !bValid ) {
    cout << "Enter an integer : ";
    getline( cin, sInLine );
    
    bNonDigit = false;
    for( size_t i = 0; i < sInLine.size(); ++i ) {
      if( !isdigit( sInLine[i] ) )
        bNonDigit = true;
    }
    
    if( bNonDigit )
      cout << "The input contains non digits - Invalid\n";
    
    else {
      istrstream InStream( sInLine.c_str() );
      InStream>> nNumber;
      if( !InStream )
        cout << "Your number is invalid\n";
      else
        bValid = true;
    }
  }
  
  cout << "You entered " << nNumber << endl;

[rarmknecht]

thanks for your replies!

Both were very helpful.