Choose a function, Fibonacci (f) or Collatz (c) [otherwise quit]:  c

Enter lower and upper bounds (two integers):  1  30

                    Recursive ver.                      Looped ver.
         n      result  steps   time                result  steps   time
        ---     ---------------------------         ---------------------------
        1       1       1       18000               1       1       5000
        2       1       2       5000                1       2       0
        3       1       8       3000                1       8       1000
        4       1       3       1000                1       3       1000
        5       1       6       2000                1       6       1000
        6       1       9       3000                1       9       2000
        7       1       17      3000                1       17      2000
        8       1       4       3000                1       4       1000
        9       1       20      2000                1       20      1000
        10      1       7       2000                1       7       1000
        11      1       15      2000                1       15      1000
        12      1       10      2000                1       10      1000
        13      1       10      2000                1       10      0
        14      1       18      4000                1       18      2000
        15      1       18      2000                1       18      1000
        16      1       5       1000                1       5       0
        17      1       13      3000                1       13      2000
        18      1       21      3000                1       21      2000
        19      1       21      6000                1       21      2000
        20      1       8       2000                1       8       1000
        21      1       8       2000                1       8       1000
        22      1       16      4000                1       16      1000
        23      1       16      4000                1       16      2000
        24      1       11      2000                1       11      1000
        25      1       24      4000                1       24      2000
        26      1       11      1000                1       11      1000
        27      1       112     18000               1       112     9000
        28      1       19      3000                1       19      2000
        29      1       19      5000                1       19      2000
        30      1       19      5000                1       19      2000