Solved

simple if question

Posted on 1998-05-08
6
195 Views
Last Modified: 2010-05-18
I have a program which asks the user for a number (float) but if the user inputs a char instead of a float it sends my program into a loop which never ends.  I want to know if there is a way to read what the user inputs and if it is a char then it will tell the user they must enter a number and repeats the orginal question.

basic example

 
float x;
cout << "enter number";
cin >> x;

if (x != char) // problem is here

cout << "Number is: " << x;
else
cout << "you must enter a number";
0
Comment
Question by:onestar
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 4
  • 2
6 Comments
 
LVL 22

Expert Comment

by:nietod
ID: 1174817
The way around this is the let the user enter a character string.  Then try to convert the string to a number (integer or real, as needed).  

As I'm not very familia with C I/O, I won't submit code examples, unless no one else can help (unlikely).
0
 
LVL 22

Expert Comment

by:nietod
ID: 1174818
By the way the character string can be converted to an integer with atoi() or to a floating point with atof().
0
 
LVL 22

Accepted Solution

by:
nietod earned 50 total points
ID: 1174819
What the heck.  I found what I needed.

char InputLine[100];

cin.getline(InputLine,100);
// You can test input line for invald characters here.  (Let me know if you need help on this.)  
float x = atof(InputLine);
0
Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 22

Expert Comment

by:nietod
ID: 1174820
Not that you can test the strign entered by the use for invalid characters, but you don't have to.  the conversion fucntions start at the beginning of the string and stop converting when they reach an invalid character.  So if the user enters "123abc" it will convert to 123.  If the user enters "abc" it will convert to 0.  This may or may not be acceptable to you as is.
0
 
LVL 2

Expert Comment

by:kellyjj
ID: 1174821
dang nietod,  you beat to the punch.  I was trying to answer the question when you did.  Damn it all to hell!!!  hehehe
0
 
LVL 2

Expert Comment

by:kellyjj
ID: 1174822
Do you mean to have an "if" in there?  like "if (x)"?
0

Featured Post

Ready to get started with anonymous questions?

It's easy! Check out this step-by-step guide for asking an anonymous question on Experts Exchange.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

C++ Properties One feature missing from standard C++ that you will find in many other Object Oriented Programming languages is something called a Property (http://www.experts-exchange.com/Programming/Languages/CPP/A_3912-Object-Properties-in-C.ht…
Go is an acronym of golang, is a programming language developed Google in 2007. Go is a new language that is mostly in the C family, with significant input from Pascal/Modula/Oberon family. Hence Go arisen as low-level language with fast compilation…
The viewer will learn how to clear a vector as well as how to detect empty vectors in C++.
The viewer will be introduced to the technique of using vectors in C++. The video will cover how to define a vector, store values in the vector and retrieve data from the values stored in the vector.

627 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question