Project Euler is a website dedicated to computational problems intended to be solved with computer programs.
At the time of this writing, it includes over 400 problems, with a new one added every week.
Problems are of varying difficulty but each is solvable in less than a minute using an efficient algorithm on a modestly powered computer.
I have already solved some of the problem, mainly using J (a language in the APL family) or Python.
Last year I learned ABAP and now, to test my skill with it, I decide to solve some of the Project Euler problem using ABAP.
To be able to execute ABAP programs, I have installed a SAP NetWeaver Trial Version ABAP (Windows) under VirtualBox.
The 4th problem (Largest palindrome product) does not need particular utility functions to be solved:
A palindromic number reads the same both ways.
The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 * 99.
Find the largest palindrome made from the product of two 3-digit numbers.
An ABAP solution is below (run the program to see the solution).
It is composed of two loops.
The variable a is assumed to be bigger or equal to b (multiplication is commutative).
The product a * b is assigned to the string s.
The blanks are removed from s with CONDENSE.
Then we check if s is equal to its reverse and if it is bigger than previous found solutions.
REPORT ZMLA_TEST4.
DATA: sol TYPE INT4 VALUE 0,
start TYPE INT4 VALUE 999,
stop TYPE INT4 VALUE 99,
a TYPE INT4,
b TYPE INT4,
num TYPE INT4,
s TYPE STRING.
a = start.
WHILE a > stop.
b = a.
WHILE b > stop.
num = a * b.
s = num.
CONDENSE s NO-GAPS.
IF s = reverse( s ) and num > sol.
sol = num.
ENDIF.
b = b - 1.
ENDWHILE.
a = a - 1.
ENDWHILE.
s = |The solution is { sol }|.
WRITE / s.
