Question about cin.getline

Hi
I was wondering how to prevent someone from typing in more than the set number of characters in an array...i have been using:

cin.getline (name, 50)

but it enters a continious loop if more than 50 chars are entered, just wodndering if theres a way around this?

thanks

There is.
Post your code that is looping infinately when over 50 chars are entered.

gg

The easy way is to use getline(cin,name) where name is a std::string. If, for some reason the first 49 characters are the only ones that are significant you can use resize(). If you must make life difficult for yourself

Code:

// Leave newline in stream, regardless of
// success, then use ignore to discard 
// any extra(plus the newline).
cin.get(name,50);
cin.ignore(numeric_limits<int>.max(),'\n');


// Check the status of failbit, if true discard
// any characters in the buffer up to and 
// including newline
if(!cin.getline(name,50)) {
    cin.clear();
    cin.ignore(numeric_limits<int>().max(),'\n');
}

The first version is simpler, but doesn't give you a chance to perform any extra processing if the line was too long for your buffer. With the second you have a chance to react to the excessive input in a more constructive manner.

Hi
Thanks for replies...have been playing around with:
cin.ignore(numeric_limits<int>.max(),'\n');
but cant get it to work.......my code is below....the original problem still is there, where if you enter over 10 chars it enters an infite loop...
it gives 'correct' when Bart and Fred are entered but when John and Steve are entered it gives correct, but then wrong...

really new to c++ so theyre probably newb errors =/

thanks

Code:

#include <iostream>
using namespace std;


int main()
{
	
	char name [4][10] =	{"John","Steve","Bart","Fred"};
	char getname [10];
	bool correct = false;

   do
	{
		cout << "name:"; 
		cin.getline(getname,10,'\n');
		

		for(int a = 0; a < 4; a++) 
		{
			int bname = strcmp (getname, name[a]);

			if (bname == 1 && a == 3)
			{
				cout << "wrong";
				cout << endl;
				correct = false;
			}


			if (bname == 0)
			{
				cout << "correct";
				cout << endl;
				cout << endl;
				correct = true;
			}
		}
	}while (!correct);

	return 0;
}

When getline fills the buffer (ie. it doesn't find the target character), it sets an error flag that must be cleared before anything else can be done with the stream. You can clear the flags with cin.clear(), then remove the extraneous characters with cin.ignore():

Code:

#include <iostream>
#include <limits>
using namespace std;

int main()
{
  char name [4][10] = {"John","Steve","Bart","Fred"};
  char getname [10];
  bool correct = false;
  
  do
  {
    cout << "name:"; 
    cin.getline(getname,10,'\n');
    if (!cin.good())
    {
      cin.clear();
      cin.ignore(numeric_limits<streamsize>::max(), '\n');
    }
    
    for(int a = 0; a < 4; a++) 
    {
      int bname = strcmp (getname, name[a]);
      
      if (bname == 1 && a == 3)
      {
        cout << "wrong";
        cout << endl;
        correct = false;
      }
      
      
      if (bname == 0)
      {
        cout << "correct";
        cout << endl;
        cout << endl;
        correct = true;
      }
    }
  }while (!correct);
  
  return 0;
}

strcmp(a,b) returns -1 if a<b and 1 iff a>b You are only checking if a > b and then only setting correct to false if the name you entered is greater than "Fred" . You want to compare getname to each name in your list and stop when you find a match. thus:

Code:

correct = false;
for(int i=0;i<4 && !correct;++i) correct = strcmp(getname,name[i]))==0;

thanks everyone...really appreciated
sorted