Question! Converting String to a double or Integer where the value is rounded up or down?

Posted on 2006-07-24
Last Modified: 2010-04-01
Hi guys,

My question is about how, when received a string& one can take that string and convert it to double,
alternatively I want the string to be converted into an integer rounded up or down ie value in from string is 1.560008 then the int = 2 etc.

Here's how I failed to convert the string& to double:

void getValue(string& theValue) {
      double d;
      char l [256];
      l = theValue;
      d = atof(theValue);
      cout << d << endl;
      cout << flush;

any inputs are welcomed

All the best
Question by:Idarhillgaar
  • 2

Accepted Solution

nafis_devlpr earned 250 total points
ID: 17166576
you can do it this way

 d = atof(theValue.c_str());


sscanf(theValue.c_str(), "%lf", &d);

for the second question, do the above then do this

int i= (int)(d+0.5);

hope this helps


Expert Comment

ID: 17166592
>> int i= (int)(d+0.5);

this will actually round the values, for example :

if 1.5 it will be 2
if 1.4 it will be 1

you can also use the ceil or floor to round-up or round-down the values, for exmple

if  1.5
then ceil(1.5) will give 2.0
and floor(1.5) will give 1.0


Author Comment

ID: 17166719
Fabulous answers - Have a good summer!


Featured Post

Free Tool: Port Scanner

Check which ports are open to the outside world. Helps make sure that your firewall rules are working as intended.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

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

Suggested Solutions

What is C++ STL?: STL stands for Standard Template Library and is a part of standard C++ libraries. It contains many useful data structures (containers) and algorithms, which can spare you a lot of the time. Today we will look at the STL Vector. …
IntroductionThis article is the second in a three part article series on the Visual Studio 2008 Debugger.  It provides tips in setting and using breakpoints. If not familiar with this debugger, you can find a basic introduction in the EE article loc…
The goal of the tutorial is to teach the user how to use functions in C++. The video will cover how to define functions, how to call functions and how to create functions prototypes. Microsoft Visual C++ 2010 Express will be used as a text editor an…
The goal of the video will be to teach the user the difference and consequence of passing data by value vs passing data by reference in C++. An example of passing data by value as well as an example of passing data by reference will be be given. Bot…

740 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