Problem 1

Problem 2
niceOpA has been invoked
niceOpB has been invoked
niceOpC has been invoked

Problem 3
(int) 3.14           is 3
5 * (2 / 5)          is 0
(5 * 2) / 5          is 2
5 + 0.0              is 5.0
1.0 / 2 / 1          is 0.5
1 / 2 / 1.0          is 0.0
(double) 3 / 2       is 1.5
true == false        is false
true || false        is true
true && false        is false
("" + 5) + 6         is "56"
"" + (5 + 6)         is "11"
"cat".length()       is 3
"cat".indexOf('a')   is 1

Problem 4

Problem 5

Problem 6
Testing ()()[][]
OK
Testing [([])[()]]
OK
Testing 
OK
Testing ()(][]
Testing (()
Testing ())