The 3x + 1 problem

README.md

The 3x + 1 problem

But as a function in some languages. I'll not explain this problem, cuz I'm not a math expert and is a well know math problem, so... More details can be found in the internet 👍

Problem.c

#include <stdio.h>
#include <stdlib.h>

int problem(int n) {
  if (n == 1) {
    printf("End\n");
    return n;
  } else if ((n % 2) == 0) {
    printf("Even: %d\n", n);
    return problem(n / 2);
  } else {
    printf("Odd:  %d\n", n);
    return problem((n * 3) + 1);
  }
}

int main(int argc, char **argv) {
  problem(atoi(argv[1]));
  return 0;
}

Problem.go

package main

import (
	"flag",
	"fmt"
)

func Problem(n int) int {
	if n == 0 {
		fmt.Println("End.\n")
		return n;
	} else if (n % 2) == 0 {
		fmt.Printf("Even: %d\n", n)
		return Problem(n / 2)
	} else {
		fmt.Printf("Odd:  %d\n", n)
		return Problem((n * 3) + 1)
	}
}

func main() {
	flag.Parse()

	Problem(int(flag.Args()[0]))
}

Problem.lua

--- The functions takes a positive integer and does the math (prints in time),
--- but ends if the number is 1 (to prevent and infinite loop).
function Problem(n)
  if n == 1 then
    print("End")
    return n
  else
    if n % 2 == 0 then
      print("Even: " .. tostring(n))
      return Problem(n / 2)
    else
      print("Odd:  " .. tostring(n))
      return Problem((n * 3) + 1)
    end
  end
end

Problem(argv[0])

Problem.nim

from os import commandLineParams
from strutils import parseInt

# The functions takes a positive integer and does the math (prints in time),
# but ends if the number is 1 (to prevent and infinite loop).
proc problem(n: int): int =
  if n == 1:
    echo "End"
    return n
  elif (n mod 2) == 0:
    echo "Even: ", n
    return problem(int(n / 2))
  else:
    echo "Odd:  ", n
    return problem((n * 3) + 1)

discard problem(parseInt(commandLineParams()[0]))

Problem.py

from sys import argv

# The functions takes a positive integer and does the math (prints in time),
# but ends if the number is 1 (to prevent and infinite loop).
def Problem(n):
  if n == 1:
    print("End")
    return n
  elif (n % 2) == 0:
    print(f"Even: {n}")
    return Problem(int(n / 2))
  else:
    print(f"Odd:  {n}")
    return Problem((n * 3) + 1)

Problem(argv[1])

Problem.vala

int problem(int n) {
  if (n == 1) {
    print("End\n");
    return n;
  } else if ((n % 2) == 0) {
    print(@"Even: $(n)");
    return problem(n / 2);
  } else {
    print(@"Odd:  $(n)");
    return problem((n * 3) + 1);
  }
}

int main(string[] args) {
  problem(int.parse(args[1]));
  return 0;
}