Collatz conjecture / 3n+1 Problem

gcc -O4 -o collatz-conjecture collatz-conjecture.c

Example output to console:

Start: 3   End: 1   Steps: 7
Start: 6   End: 1   Steps: 8
Start: 7   End: 1   Steps: 16
Start: 9   End: 1   Steps: 19
Start: 18   End: 1   Steps: 20
Start: 25   End: 1   Steps: 23
Start: 27   End: 1   Steps: 111
Start: 54   End: 1   Steps: 112
Start: 73   End: 1   Steps: 115
Start: 97   End: 1   Steps: 118
...
Start: 12235060455   End: 1   Steps: 1184
...