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I am trying to align the console output in C++ to a decimal point. I have tried the setw, precision options and other flags that aligns to right or left.

But none of those has worked satisfactorily.

The closest option is to use showpos to print (+) sign for positive numbers, but it disturbs the other formatting such as "TE_1_0" to "TE_+1_+0"

1.000000    -0.000000   0.000000
-0.000000   1.000000    0.000000
0.000000    0.000000    1.000000

It will be nice to have it aligned to decimal point to present the output to the people who are interested in. So any help will be much appreciated.

jomegaA
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1 Answers1

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You can do this with a combination of setw, setfill, fixed and setprecesion as follows:

#include <iostream>
#include <vector>
#include <iomanip>

int main()
{
    std::vector<std::vector<double>> vec{{10.0233, 122.1, 1203.1},{100.03, 22.15, 3.01},{107.03, 152.1, 0.1},};
    for(std::vector<double> tempVec: vec)
    {
        for(double elem: tempVec)
        {
            std::cout << std::setw(8) << std::setfill(' ') << std::fixed << std::setprecision(3) << elem << "    ";
        }
        std::cout<< std::endl;
    }
    return 0;
}

The output of the above is:

  10.023     122.100    1203.100    
 100.030      22.150       3.010    
 107.030     152.100       0.100

If you modify the above example slightly as shown below:

std::cout << std::setw(12) << std::setfill(' ') << std::fixed << std::setprecision(6) << elem << "    ";

Then the output becomes:

   10.023300      122.100000     1203.100000    
  100.030000       22.150000        3.010000    
  107.030000      152.100000        0.100000

setw is used to set the maximum length of the output, which was 8 and 12 in my given example.

setfill is used to fill the padding places with a char.

Jason
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