issotm / numflip-golf

Code golfing contest: flip a number's digits

numflip-golf

Code golfing contest: flip a number's digits!

Rules

Goal

Write a function or method that takes an integer between -999,999,999 and 999,999,999 (inclusive), and returns the integer whose decimal digits are flipped. Try making the source code as small as possible!

Examples: flip(5678) == 8765, flip(-541) == -145, flip(-100) == -1.

Scoring

• Each character part of the function counts for 1 point, including spaces and newlines
• The lower the amount of points, the better
• Import / preproc directives, any global variables, etc. required for the function to work are counted as well
• If using an online compiler (such as tio.run), any "boilerplate" necessary for the program to run will not be counted (main function, etc.), unless it falls into the clause above
• For readability, newlines and comments that do not matter to the functionality will not be counted
• Execution time and memory footprint are not relevant; it just needs to terminate eventually

Languages

All languages are allowed, with one leaderboard per language. (If you do it in Java, you'll still stand a chance to be #1!). Esoteric languages are accepted, but less relevant to this kind of challenge.

Constraints

• The function parameter and return types must be numeric, unless the language makes that impossible (such as bash)
• Non-standard imports are not allowed, even if popular (so no boost, lodash, numpy...)
• The program execution must be deterministic
• Relying on language extensions will be allowed on a case-by-case basis
• Lambdas are accepted, but only if stored in a named variable (so they can be called like a normal function)
• The code must be self-sufficient, thus it may not rely on external files, the program's file name, or touch the file system

Provision

• The rules may be changed at any time to patch loopholes
• Rule-bending submissions are accepted, and will be scored separately (see the troll)
• Anything litigious will be left to my own discretion :)