Solve Lewis Carroll Doublet or Word Golf Puzzles

LADDERS, a C program which seeks to transform one five letter word into another, by changing one letter at a time, using only legitimate English words. This puzzle was invented by Lewis Carroll, who called it "Doublets", but it is also known as "Word Ladders" or "Word Gold". The program is by Donald Knuth.


The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.


LADDERS is available in a C version.

Related Data and Programs:

ANAGRAM, a C++ program which determines anagrams of a string, by James Cherry;

LIFE_OPENGL, a C program which uses OpenGL to display the evolution of John Conway's "Game of Life", by Simon Green.

LIGHTS_OUT_OPENGL, a C++ program which sets up a "Lights Out" game and allows the user to solve it, using the OpenGL graphics window.

SGB, a dataset directory which contains files used as input data for demonstrations and tests of Donald Knuth's Stanford Graph Base.

SUBANAGRAM, a FORTRAN90 program which finds words which are anagrams formed from some of the letters of a given master word.

SUDOKU, a MATLAB library which manipulates and solves Sudoku problems.

WORDS, a dataset directory which contains lists of words.

WORDSNAKE, a FORTRAN90 program which rearranges a list of words so that they have maximum overlap;


  1. Charles Lutwidge Dodgson,
  2. Donald Knuth,
    The Stanford Graph Base,
    ACM Press, 1993.

Source Code:

You can go up one level to the C source codes.

Last revised on 19 October 2016.