Solved

output string formatting

Posted on 1998-09-09
7
279 Views
Last Modified: 2010-04-10
Hi, in C one uses " %4.3lf " to string format a long double floating point value. And " %4.3f " for ordinary floating point values.

What is its  equivalent in C++ ? (i.e. for long double string formating)

I tried using setprecision(4), but this messes up the output which returns with a string of # signs and some alphanumeric characters.

setprecision() is meant for normal/ordinary floating point values, but I don't know which is the equivalent parameter for long double floating point values .

Thanks

Paul
0
Comment
Question by:pdorai
  • 2
  • 2
  • 2
  • +1
7 Comments
 
LVL 6

Accepted Solution

by:
WxW earned 30 total points
ID: 1172316
The same . Functions included in stdio.h as printf are available to C++ . Furthermore , if your app is a windows app , use sprintf to create a buffer to format the text
0
 
LVL 22

Expert Comment

by:nietod
ID: 1172317
WxW, I think pdorai is trying to use streams.  Thus, the converting back to the C way is not a good idea.

setprecision(4) is not 100% equiviliant to C's %4.3f.  the precision is used in two ways.  If the stream is in automatic format or scientific format, then it will display 4 significant digits.  If the stream is in fixed format it will display 4 decimal digits.  You may need to set the width prior to ouputing the number to get the desired result.  
0
 
LVL 6

Expert Comment

by:snoegler
ID: 1172318
In my opinion is every C function also a C++ function - but i think that's bad karma, right?
0
Gigs: Get Your Project Delivered by an Expert

Select from freelancers specializing in everything from database administration to programming, who have proven themselves as experts in their field. Hire the best, collaborate easily, pay securely and get projects done right.

 
LVL 22

Expert Comment

by:nietod
ID: 1172319
Yes, but in many cases C++ provides improved ways to perform tasks that are not available in C.  C++'s I/O streams are an example.  They are more powerful and are much safer to use.  
0
 
LVL 6

Expert Comment

by:WxW
ID: 1172320
C++ streams are more powerful than printf and sprintf ?
For creating simple buffers ... I think that they are better & easier
0
 
LVL 2

Expert Comment

by:Paullkha
ID: 1172321
Here's a couple of ways!

CString text; //string???
float value = 1.30;
text.Format("$%7.2f", value);
(I like the above because you can easily see the formatting AND you are not changing the setup for cout)
or

cout.precision(4);
cout << 1.3456;

or

ios_base::fixed

etc...


0
 
LVL 2

Expert Comment

by:Paullkha
ID: 1172322
#include <iostream>
#include <iomanip>
using namespace std;

int main()
{
      long double x;
      x = 12.3456;
      cout << setprecision(2) << fixed << setw(5) << x <<endl;
      return (0);
}
Is this what you want?
fixed is fixed decimal point
setprecision, as mentioned above, sets number of digits AFTER decimal point
setw sets the width to 5, this width INCLUDES the decimal point
Good luck
0

Featured Post

Courses: Start Training Online With Pros, Today

Brush up on the basics or master the advanced techniques required to earn essential industry certifications, with Courses. Enroll in a course and start learning today. Training topics range from Android App Dev to the Xen Virtualization Platform.

Question has a verified solution.

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

When writing generic code, using template meta-programming techniques, it is sometimes useful to know if a type is convertible to another type. A good example of when this might be is if you are writing diagnostic instrumentation for code to generat…
This article will show you some of the more useful Standard Template Library (STL) algorithms through the use of working examples.  You will learn about how these algorithms fit into the STL architecture, how they work with STL containers, and why t…
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 member functions push_back and pop_back of the vector class. The video will teach the difference between the two as well as how to use each one along with its functionality.

813 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

Need Help in Real-Time?

Connect with top rated Experts

11 Experts available now in Live!

Get 1:1 Help Now