CODEWITHSUNDEEP
c++inputenumsswitch-statement
ficabj5
ficabj5

Reputation: 111

Restricting user input

I am making a simple program, where user needs to enter a few possible characters. I want possible inputs to be only i, c, l, v, h, k, f, s, x. I do realize I can do something like:

char a;
bool s(false);    
cin>>a;
do
{
switch(a)
case 'i': ...
case 'c': ...
...
default: cout<<"Invalid input! Try again: "; cin>>a; s=true;
} while(s);

However, I am pretty sure there is a more gracious solution. I am guessing enumerations would be involved. Would anyone be so kind as to tell it to me, since I could not find absolutely anything on the subject.

Upvotes: 2

Views: 79

Answers (1)

Christophe
Christophe

Reputation: 73426

An easy solution could be: 

const string allowed{"iclvhkfsx"};
while (  cin.get(a) && allowed.find(a)== string::npos)
   cout << "Incorect input, try again ! ";

The code loops until a valid char is entered (or eof is reached).

Online demo

Such a solution could be generalized to other data types than chars by using basic_string<T> (demo for integers). Of course, switch is perfectly valid, but I think its benefit is higher whenever different input would most often require different processing.

Upvotes: 3

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