C++ How to restrict input to one char at a time?

Question

I have a program that asks the user to enter input several times, and stores that input in different char variables, and then does things to those variables.

My problem is that I want to restrict the input to work for one variable at a time. For example:

char a = 'a', b = 'b', c = 'c';
cout << "Enter a ";
cin  >> a; 
cout << "\nEnter b ";
cin  >> b;
cout << "\nEnter c ";
cin  >> c;

cout << "Entered chars were " << a << ", " << b << ", " << c;

Running this, if the user enters t y u (including the spaces between the letters) will make the program to enter t into variable a, y into variable b, and u into variable c. Essentially, it would sort of "fall through" and automatically put values for cin rather than asking the user to do it for each one.

What I want, is to check that what the user enters for variable a is 1 char only.

I have tried using cin.good(), however it returns a 0 after entering more than one character for cin >> a; I have also tried using cin.get(a); and then checking for cin.good(). This also returns 0 if user enters more than one character.

Is there a way to restrict the input to work for only one cin operation at a time?

You can just call ignore to kill the rest of the input (slowly and painfully). — Qaz
– Qaz, Commented Mar 22, 2013 at 16:52
Use getline to get one line at a time. Discard any excess values on each line. — john
– john, Commented Mar 22, 2013 at 16:53

Armen Tsirunyan · Accepted Answer · 2013-03-22 16:53:29Z

10

You should read your input line by line and then parse it. As such

std::cout << "Enter a:\n";
std::string input;
std::getline(std::cin, input);
if(input.length() != 1)
   //error
else
   char a = input[0];

answered Mar 22, 2013 at 16:53

Armen Tsirunyan

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vsmph · Accepted Answer · 2013-03-22 17:06:47Z

3

From C language . You can use getch(); which take only one char at a time .

If you want to multiple characters , i mean string . you use getch(); with in loop. getch() is from conio.h and getche() also available to display on console.

answered Mar 22, 2013 at 17:06

vsmph

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