Code:

version 1. if a < b and a < c
if b < c
cout a b c
else
cout a c b
else if b < a and b < c
if a < c
cout b a c
else
cout b c a
etc.
version 2. if a = = smallest
if b < c
etc
version 3. look up bubble sort by searching the board or the web or your instructional book. its a general sort algorhythm that will work for array/list of any size and not specific to just three values, like version 1 and 2. It can also be used to sort largest to smallest. It's not the most sophisticated sorting algorhythm, and for larger groups of values it's not the fastest, but it is among the easiest code to write.