s1: ---
s2: < 1 12 13 33 >
s3: < 12 13 17 88 >
s4: ---
s1 is empty.
s2 is not empty
s1.insertElement(20):
< 20 >
s2.deleteElement(33):
< 1 12 13 >
s1 = s2.unionOfIntegerSets(s3):
< 1 12 13 17 88 >
s1 = s2.intersectionOfIntegerSets(s3):
< 12 13 >
s1.intersectionOfIntegerSets(s4)
---
End of driver program.