printf, sprintf print at least two decimal places

Question

I'm trying to figure out how to use sprintf to print at least two decimal places and no leading zeros. For instance

input:

23
23.0
23.5
23.55
23.555
23.0000

output:

23.00
23.00
23.50
23.55
23.555
23.00

any formatting help would be appreciated

Answer 1

There is no such built-in format specifier. You could check if the number to be printed as two or fewer decimals (round to two decimals and compare), and if so use %.02f. If the number has more decimals, use a %g specifier. Here's an example in Ruby:

def print_two_dec(number)
  rounded = (number*100).to_i / 100.0
  if number == rounded
    printf "%.02f\n", number
  else
    printf "%g\n", number
  end
end

[ 23, 23.0, 23.5, 23.55, 23.555 ].each do |number|
  print_two_dec(number)
end

Outputs:

23.00
23.00
23.50
23.55
23.555