Linked Questions

130
votes
285answers
27k views

Shortest code to produce infinite output

Write the shortest code you can that produces an infinite output. That's all. You code will only be disqualified if it stops producing output at some point. As always in code golf, the shortest code ...
88
votes
273answers
17k views

Simple cat program

One of the most common standard tasks (especially when showcasing esoteric programming languages) is to implement a "cat program": read all of STDIN and print it to STDOUT. While this is named after ...
221
votes
106answers
40k views

Print every character your program doesn't have

Your task is to build a program (using only printable ASCII characters and/or tabs and newlines) that prints out exactly the characters in the printable ASCII space (...
122
votes
187answers
31k views

Sing Happy Birthday to your favourite programming language

Your favourite programming language has just had a birthday. Be nice and sing it the Happy Birthday song. Of course you should accomplish this by writing a program in that language. The program takes ...
376
votes
38answers
54k views

Covfefify a string

In this challenge, you must take a string matching the regex ^[a-zA-Z]+$ or whatever is reasonable (you don't have to consider uppercase or lowercase letters if you ...
61
votes
210answers
8k views

The Mystery String Printer (Cops)

The robbers thread can be found here: The Mystery String Printer (Robbers) Your challenge Write a program, function, or REPL script that prints a string to STDOUT. The robbers will try to create a ...
107
votes
93answers
16k views

Loading… Forever

Your challenge is to make an infinite loading screen, that looks like this: Or, to be more specific: Take no input. Output Loading..., with a trailing space, but ...
86
votes
104answers
11k views

N(e(s(t))) a string

To "function nest" a string, you must: Treat the first character as a function, and the following characters as the arguments to that function. For example, if the input string was ...
89
votes
79answers
23k views

It took me a lot of time to make this, pls like. (YouTube Comments #1)

Hold up..... this isn't trolling. Background These days on YouTube, comment sections are littered with such patterns: ...
58
votes
118answers
15k views

Duck, duck, goose!

Remember the kids game, 'Duck, Duck, Goose'? No? Me neither. The challenge Print the word 'duck' on individual lines an indeterminate amount of times. Print the word 'goose'. Your program ends. The ...
44
votes
132answers
6k views

Full Width Text

Full width text is text that has a space after every character, including the last one. For instance, the first sentence of this question becomes: ...
74
votes
64answers
17k views

Sing Baby Shark

"Baby Shark" is a children's song about a family of sharks. Having long been popular as a campfire song, it has been popularized since the mid-2000s by social media, online video and radio. - ...
65
votes
73answers
10k views

Make the Mexican Wave

In as few bytes as possible, write a program or function that outputs the following: ...
83
votes
35answers
9k views

Tips for golfing in <all languages>

The aim of this post is to gather all the golfing tips that can be easily applied to <all languages> rather than a specific one. Only post answers that its ...
56
votes
79answers
11k views

Play the “bzzt” game

Winner: Aditsu's CJam answer! A whopping 25 bytes! Nice! You may continue to submit your answer, however you can no longer win. Original post kept for posterity: The "Bzzt" game is a game ...
49
votes
88answers
8k views

Alphabet triangle

You are to print this exact text: ...
92
votes
48answers
6k views

5 Favorite Letters

The challenge is actually extremely simple. Pick 5 distinct letters (you can just pick the 5 that allow you the shortest code if you like) and output them to the console. However, the twist is that ...
41
votes
98answers
15k views

Is this number evil?

Introduction In number theory, a number is considered evil if there are an even number of 1's in its binary representation. In today's challenge, you will be identifying whether or not a given number ...
44
votes
91answers
5k views

StringgnirtSStringgnirtSStringgnirtS

Here is a relatively simple challenge for you. Given a string of length N, output the string forwards, then backwards, then forwards, then backwards... etc. N times. For example, if your input was <...
71
votes
50answers
8k views

Score rock-paper-scissors

Given two string inputs of "Rock", "Paper", or "Scissors", determine the outcome of the RPS round. Output 1 if the first player wins, -1 if the second player wins, or 0 for a tie. ...
44
votes
73answers
13k views

Hack into a Lottery

You've recently made an account on a dodgy gambling site, where for a fee of 25 dollars, they will pay you back a random amount between 0 and 50 dollars. After getting around 5 dollars twice, you ...
50
votes
66answers
18k views

Helloellolloloo Worldorldrldldd

Make a program that takes the word you input, and adds that word to the back of itself minus its first letter, then repeats until all letters are gone. For example, ...
62
votes
62answers
8k views

Lossy Sorting (Implement Dropsort)

Dropsort, designed by David Morgan-Mar, is an example of a linear-time "sorting algorithm" that produces a list that is, in fact, sorted, but contains only some of the original elements. Any element ...
46
votes
69answers
7k views

Make an Emergency Corridor

In some nations there are recommendations or laws on how to form emergency corridors on streets that have multiple lanes per direction. (In the following we only consider the lanes going in the ...
37
votes
88answers
6k views

Print all alphanumeric characters plus underscore

Write a program or function that prints or returns a string of the alphanumeric characters plus underscore, in any order. To be precise, the following characters need to be output, and no more: ...
76
votes
43answers
10k views

Fibonacci + Fizz Buzz = Fibo Nacci!

Fibonacci + FizzBuzz = Fibo Nacci! Your challenge is to create a Fibo Nacci program! A Fibo Nacci program outputs the first 100 Fibonacci numbers (starting from 1). If the Fibonacci number is ...
35
votes
78answers
7k views

Notcalc (Calculate the wrong answer)

Goal: Given two natural numbers (integers from 0 to infinity), output a number that is not the sum of those numbers, but is a natural number. Example solutions (TI-Basic): ...
67
votes
50answers
10k views

My daughter's alphabet

The other day we were writing sentences with my daughter with a fridge magnet letter. While we were able to make some(I love cat), we didn't have enough letters to ...
58
votes
52answers
10k views

How much code would a codegolf golf if a codegolf could golf code?

Write a function or program that takes two words as input and outputs variants of the popular English tongue-twister "How much wood would a woodchuck chuck if a woodchuck could chuck wood?". The ...
43
votes
66answers
5k views

Blinking twelve

Many electronic devices, specially old ones, will show a blinking 12:00 when the time has not been set. The purpose of this challenge is to recreate this. ...
32
votes
75answers
4k views

Sum the numbers on standard in

Consider a stream/file with one integer per line. For example: 123 5 99 Your code should output the sum of these numbers, that is ...
54
votes
50answers
7k views

Convert YYYYMM to MMMYY

Basing on this SO question. Challenge is rather simple: given a date period in the format YYYYMM output it in the format MMMYY. ...
28
votes
88answers
4k views

Generate alphabet with 4 copies of each letter

Note that this is not the same as Print the alphabet four times. This task is to write a program to generate four copies of each letter of the English alphabet, one letter per line, on standard ...
46
votes
43answers
5k views

Tips for golfing in PowerShell

What general tips do you have for golfing in Windows PowerShell? I'm looking for ideas that can be applied to code golf problems in general that are at least somewhat specific to PowerShell (e.g. "...
51
votes
43answers
6k views

Coprimes up to N

Given a number n >= 2, output all the positive integers less than n where gcd(n, k) == 1 (...
68
votes
27answers
13k views

418: I'm a teapot

As we all should know, there's a HTTP status code 418: I'm a teapot. Your mission, should you choose to accept it, is to use your creativitea and write the smallest possible server that responds with ...
26
votes
81answers
4k views

Is it a whole number?

A number is whole if it is a non-negative integer with no decimal part. So 0 and 8 and ...
29
votes
69answers
8k views

Randomizing until 0

Challenge Sandbox post Given a positive integer (K) Output a uniformly-random integer (Y) between ...
34
votes
56answers
6k views

Capitalize first letter of each word of input

This is a relatively quick one, but I'm sure you'll like it. Codegolf a program that will take input in the form of a sentence and then provide the output with the first letter capitalized in each ...
53
votes
27answers
14k views

Tips for golfing in C++

What general tips do you have for golfing in C++? I'm looking for ideas that can be applied to code golf problems in general that are at least somewhat specific to C++ (e.g. "remove comments" is not ...
70
votes
23answers
7k views

Well that's odd… no wait, that's even!

Preamble Integers are always either even or odd. Even integers are divisible by two, odd integers are not. When you add two integers you can infer whether the result will be even or odd based on ...
72
votes
16answers
17k views

Draw the ☣ (Biohazard Symbol)

Draw the Biohazard symbol in an arbitrary colour on a distinctly coloured background. The specific proportions were published in the June 27th 1974 issue of the Federal Register of the US Government. ...
56
votes
29answers
23k views

Cheat at Rock-Paper-Scissors-Lizard-Spock

When playing Rock-Paper-Scissors-Lizard-Spock, your robot reflexes let you see your opponent's throw before they make it. You just need to choose a throw that beats theirs, in as few bytes as possible ...
39
votes
43answers
5k views

Find the needle in the haystack

Given a rectangular haystack of size at least 2x2 composed of all the same printable ASCII characters, output the location (counting from the top-left) of the needle which is a different character. ...
42
votes
29answers
7k views

Nth term of Van Eck Sequence

Output the Nth term of the Van Eck Sequence. Van Eck Sequence is defined as: Starts with 0. If the last term is the first occurrence of that term the next term is 0. If the last term has occurred ...
31
votes
30answers
5k views

Is it a Bumpy Word?

(inspired by this challenge over on Puzzling -- SPOILERS for that puzzle are below, so stop reading here if you want to solve that puzzle on your own!) If a letter in a word occurs alphabetically ...
27
votes
43answers
5k views

Diamond creator +

Challenge : Given an integer n as input. Create a diamond that is 2x the given number n. Input : Input is integer ...
25
votes
48answers
1k views

A list of number modulus their indices in the list

A simple one: Take a list of positive integers as input and output the numbers modulus their 1-based index in the list. If the input integers are ...
23
votes
51answers
6k views

Is string X a subsequence of string Y?

Given strings X and Y, determine whether X is a subsequence of Y. The empty string is regarded as a subsequence of every string. (E.g., '' and ...
50
votes
24answers
7k views

Minecraft Mirrored

This is Calvin. Just trying to get 20 rep so this user can chat in the PPCG Minecraft Server chatroom. Write a program or function that takes in a positive integer. If the integer is even (2, 4, 6, ....

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