Q:

C++ output alignment

#include <iostream>
#include <iomanip>

using namespace std;

int main()
{

    double start_temp, end_temp, incr, fahrenheit, celsius, kelvin;
    do
    {
        cin >> start_temp >> end_temp >> incr;
        if (start_temp > end_temp || incr <= 0)
        {
            cout << "Starting temperature must be <= ending temperature and increment must be > 0.0\n";
        }
    } while (start_temp > end_temp || incr <= 0);
    cout << fixed << setprecision(4);

    cout << "\n"
         << left << setw(18) << "Fahrenheit" << right << setw(18) << "Celsius" << setw(18) << "kelvin";

    for (fahrenheit = start_temp; fahrenheit <= end_temp; fahrenheit = fahrenheit + incr)

    {
        celsius = (fahrenheit - 32) / 1.8;
        kelvin = celsius + 273.15;

        cout << "\n"
             << left << setw(18) << fahrenheit << right << setw(18) << celsius << right << setw(18) << kelvin;
    }

    return 0;
}

The numbers should be 18 characters wide with 4 digits of precision and need to be in fixed format.  Do not use tab characters (\t) to output the values..........
This what  I am getting for my ouput: 
-30 100 20

Fahrenheit                   Celsius            kelvin
-30.0000                    -34.4444          238.7056
-10.0000                    -23.3333          249.8167
10.0000                     -12.2222          260.9278
30.0000                      -1.1111          272.0389
50.0000                      10.0000          283.1500
70.0000                      21.1111          294.2611
90.0000                      32.2222          305.3722

My numbers in Fahrenheit column are not aligned correctly........
I want my output to appear exactly like theses
Here is a sample run with valid input:
-30 100 20
The output would be:
    Fahrenheit           Celsius            Kelvin
      -30.0000          -34.4444          238.7056
      -10.0000          -23.3333          249.8167
       10.0000          -12.2222          260.9278
       30.0000           -1.1111          272.0389
       50.0000           10.0000          283.1500
       70.0000           21.1111          294.2611
       90.0000           32.2222          305.3722

Consider this input:
100.5 110.4 5
The valid output will be:
    Fahrenheit           Celsius            Kelvin
      100.5000           38.0556          311.2056
      105.5000           40.8333          313.9833

I am kind stuck. Please help

A:

You have left alignment when it should be right. 
cout << "\n"
     << right << setw(18) << "Fahrenheit" << right << setw(18) << "Celsius" << setw(18) << "kelvin";

...
cout << "\n"
         << right << setw(18) << fahrenheit << right << setw(18) << celsius << right << setw(18) << kelvin;
}

Running sample
Output:
        Fahrenheit           Celsius            kelvin
          -30.0000          -34.4444          238.7056
          -10.0000          -23.3333          249.8167
           10.0000          -12.2222          260.9278
           30.0000           -1.1111          272.0389
           50.0000           10.0000          283.1500
           70.0000           21.1111          294.2611
           90.0000           32.2222          305.3722

