Write a program that computes the sum of all the floating point numbers on the command line.
C:\Source\>sum +45.3 -12 89.4 -23.56 123 sum: 222.140000
Note that the user might enter numbers without decimal points and numbers
with leading + or - signs. This is fine. atof() can be used with
these strings. Two or more +- signs will not work, though, and atof()
will return 0.0 for such strings.