4. The Final Countdown
Note: In this problem, you’re asked to enter an APL expression (some APL code), including arguments (data given to APL symbols). Your code will be tested by the APL Challenge system to check whether it gives the correct answer and uses the methods described below.
Symbols that are used to change data are called functions. For example, APL uses the function × (Times) for multiplication.
An APL function takes the result of all code to its right as its right argument (the data on the right of the symbol). For example, 2×3+4 gives 14 (rather than the 10 you might expect) because the × takes the result of 3+4 as its right argument.
The ⌽ function (Reverse) reverses a list (the symbol looks like a reflection in a mirror). For example, ⌽ 1 2 3 gives 3 2 1.
Using ⌽ and ⍳ from problem 1, create the list of whole numbers from 107 down to 101. The result should be 107 106 105 104 103 102 101.