Apparatus and method for sorting a list of items

In a radix sorting method for computing equipment, in which words are sorted by association with their individual characters, said characters in said words consisting of any computer recognizable character including alphabetic letters, numbers, or other character represented by the American Standard Code for Information Interchange, the steps comprising:

• (a) assigning a wordtracker array equal in length to a list of words being sorted, said wordtracker array being a single-dimensional array of integers in a computers memory, each memory location in said wordtracker being identified, or located in memory, by its index, with the result that each memory location in wordtracker is identified by one index, and each memory location itself holds one integer;
• (b) assigning a letter tracker array equal in length to the number of characters in the longest word in the list, and equal in width to the range of values of the characters being sorted, such as 0 through 9 for numerical sorting or 0 through 255 for the full range of computer recognizable characters, said lettertracker array being a two dimensional array of integers in a computers memory, one dimension corresponding to the position of a particular character in a word, counting the first character as being in the first position, the second character as being in the second position, and so on, and the other dimension corresponding to the ASCII values of characters, ranging in count from 0 through 255, with the result that each memory location in said lettertracker is identified, or located in memory, by its two indexes, one index corresponding to the position of a character in a word and the other index corresponding to the ASCII value of that same character, and the memory location itself holds one integer;
• (c) initializing all memory locations in said wordtracker and said lettertracker to zero, so that the integer zero is stored in all memory locations of both arrays before sorting begins;
• (d) the steps of storing different integers in said wordtracker and said lettertracker, changing the integer in one memory location at a time, as sorting proceeds, according to the following steps:
• (1) after a character of a word is examined, as is the manner of radix sorting, locating the particular memory location in lettertracker that corresponds to the letter just examined,so that one index of lettertracker corresponds to the position of the character in the word, and the other index corresponds to the ASCII value of that same character, and once located, the integer held at that location is put into a certain memory location in wordtracker in the following manner:
• (2) wordtracker receives the integer just located in lettertracker and stores that same integer in its next memory location, said next memory location is determined in one of two ways:
• (i) during the first sorting pass, in which the first character of each word is being examined, as in the manner of radix sorting, the next memory location of wordtracker is found by the sequential counting of its index, so that the first memory location is used for processing the first word, the second memory location is used for processing the second word, and so on;
• (ii) during subsequent sorting passes, in which the second or following characters of each word is being examined, as is the manner of radix sorting, the next memory location used in wordtracker is not necessarily sequential, but rather is located either by the integer held in the previously accessed location of lettertracker when the word being processed is the first in a group of words, or by the integer held in the previously accessed location of wordtracker when the word being processed is the second or following word in a group of words, such that said integer previously accessed (whether from wordtracker or from lettertracker) corresponds to an index of wordtracker, said index being wordtrackers said next memory location, so that if the integer previously accessed were 10, then the next memory location used in wordtracker would be 10, in a like manner, the integer held in the newly located memory position in wordtracker, before said integer is replaced, will locate the next memory location in wordtracker where the next integer is to be stored;
• (3) after wordtracker receives said integer from lettertracker, then lettertracker receives a new integer which is stored in the identical memory location previously located in lettertracker, replacing the integer that was formerly held there, said new integer corresponding to the memory location, or index, of wordtracker most recently located, so that lettertracker remembers the last accessed location of wordtracker.