Thread: formatting cout

I have a point, let's say a 3D.
Of course the coordinates can be any value in Real.
I want them to be printed nicely.

I used (from std) filled, setw, width, left, right, internal and more but I can not get what I want. I can do it with printf, but I want to learn the C++ way.

For example, if I have:

Code:

-1    2     1.68787
1.132536 4 21.3

I want to be printed like this:

Code:

-1           2     1.68787
 1.132536    4     21.3

In other words, I want the coordinates to be alligned.

Can you show the printf statement that generates that output?

I should have done it from the first post! Sorry.
What actually troubles me with printf, except the fact that this is C, is that I have to know the exact max number of the digits of the coordinates. However, setting a usually big number does not seem a problem, is it?

Code:

printf("%5f %5f %5f\n", vertices[i].x(), vertices[i].y(), vertices[i].z()); // same for 2 instead of 5

Code:

0.000000 1.000000 1.618034
0.000000 1.000000 -1.618034
0.000000 -1.000000 -1.618034
0.000000 -1.000000 1.618034
1.000000 1.618034 0.000000
1.000000 -1.618034 0.000000
-1.000000 1.618034 0.000000
-1.000000 -1.618034 0.000000
1.618034 0.000000 1.000000
1.618034 0.000000 -1.000000
-1.618034 0.000000 1.000000
-1.618034 0.000000 -1.000000

Code:

printf("%10f %10f %10f\n", vertices[i].x(), vertices[i].y(), vertices[i].z());

Code:

Vertices = 12
  0.000000   1.000000   1.618034
  0.000000   1.000000  -1.618034
  0.000000  -1.000000  -1.618034
  0.000000  -1.000000   1.618034
  1.000000   1.618034   0.000000
  1.000000  -1.618034   0.000000
 -1.000000   1.618034   0.000000
 -1.000000  -1.618034   0.000000
  1.618034   0.000000   1.000000
  1.618034   0.000000  -1.000000
 -1.618034   0.000000   1.000000
 -1.618034   0.000000  -1.000000

Try this:

Code:

printf("% 6.2f  % 6.2f  % 6.2f\n", vertices[i].x(), vertices[i].y(), vertices[i].z());

Note the space before the 6 (and the limit to 2 decimal points).
The space causes a space to be printed in from of a positive number.

I know it's not C++ yet, but ....

I do not want the decimal points to be hided. The printf already gave me good results. With a little bit of search, I can get good² results.
I am interested in C++ however. Thanks for the suggestion by the way!

Code:

printf("% 10f  % 10f  % 10f\n", vertices[i].x(), vertices[i].y(), vertices[i].z());

Something like this would be nice in C.

I was curious about your initial post in which some of the numbers didn't show any decimal places (trailing zeroes). I was wondering about the printf format that achieved that. But I gather that you don't mind having the trailing zeroes, which is good.

So what about:

Code:

    std::cout << std::setw(-10) << vertices[i].x() << "  "
              << std::setw(-10) << vertices[i].y() << "  "
              << std::setw(-10) << vertices[i].z() << '\n';

Your code gave me:

Code:

0  1  1.61803
0  1  -1.61803
0  -1  -1.61803
0  -1  1.61803
1  1.61803  0
1  -1.61803  0
-1  1.61803  0
-1  -1.61803  0
1.61803  0  1
1.61803  0  -1
-1.61803  0  1
-1.61803  0  -1

which is not any special formatting.. :/

What do you expect for free?
I must have ran the C code instead because it looked great!
But now that I try it again, you're right. It sucks.
Sorry about that.

No problem. If no C++ solution comes up, I am going to go for the printf version.

Maybe this can do the trick.

Code:

std::cout<<std::setfill (' ')<<std::left<<std::setw(10)<<vertices[i].x()<< " " <<
                 std::setfill (' ')<<std::left<<std::setw(10)<<vertices[i].y()<<  " " << 
                 std::setfill (' ')<<std::left<<std::setw(10)<<vertices[i].z()<< "\n";

Or this

Code:

    std::cout.setf(std::ios::fixed, std::ios::floatfield);
    std::cout << std::setw(10) << vertices[i].x() << "  "
              << std::setw(10) << vertices[i].y() << "  "
              << std::setw(10) << vertices[i].z() << '\n';

The only problem with that is that it looks terrible.
This does what he originally wanted:

Code:

#include <iostream>
#include <iomanip>

void out(double x, double y, double z)
{
    std::cout << std::setw(12) << x << ' '
              << std::setw(12) << y << ' '
              << std::setw(12) << z << '\n';
}

int main()
{
    std::cout << std::setfill(' ') << std::right << std::fixed;
    out(-1,       -1.61803,  0);
    out( 1.61803,  0,        1);
    out(-1,       -1.618034, 0);
    return 0;
}

/* Output:

   -1.000000    -1.618030     0.000000
    1.618030     0.000000     1.000000
   -1.000000    -1.618034     0.000000
*/

Thank you both. oogabooga's solution is very good.

You are right. That's ok.