Menu validation

[paistede]

I am trying to create a calculator program and want to make sure a character is not accepted (e.g g) and the user is asked to input another number. Here is the code i am using inside the SWITCH. How do I make it so the menu will only accept numbers and restart if a number is not entered?

Num1 and num2 are doubles and the cases are char.


case '1' :cout << "Input first number: ";
cin >> num1;


while (!cin);
{

cout << "Input first number: ";
cin >> num1;
cout << "\n";

}

cout << "Input second number: ";
cin >> num2;
cout << "\n";

while (!cin);
{

cout << "Input second number: ";
cin >> num2;

}

cout << fixed << showpoint << setprecision(2);

cout << "--------------------------------\n\n" ;

cout << num1 << " + "<< num2 << " = "<< num1 + num2 << "\n";//Solution

break;

[abhishekm71]

I think if you just remove the semicolons after while () and add cin.clear() and cin.ignore() in your while loops as shown below, it should work. but again i'm not sure

while (!cin) // remove the semicolon
{
 cin.clear(); //add this statement to clear the error status.
 cin.ignore(256,'\n');
 cout << "Input first number: ";
 cin >> num1;
 cout << "\n";
}

[TheIdeasMan]

Put the switch inside a while loop, and make sure the switch has a default: case to catch bad input, like in this example :

http://www.cplusplus.com/forum/beginner/104553/2/#msg564228

HTH

Edit: And please always use code tags in the future. Edit your post, select all the code, press the <> button on the right under format menu.

http://www.cplusplus.com/articles/jEywvCM9/