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Unformatted text preview: CS 31: Introduction to Computer Science I: Winter 2010: Project 3 Solution Page 1 // UCLA Winter 2010 // CS 31 Project 3 // John A. Rohr // February 4, 2010 // // // String Encoder // // This program generates coded output strings from uncoded input strings. // // The program use a single key character in the coding algorithm to alter the // string characters. A numeric checksum is attached to the end of each message. // // For simplicity, the key character is prepended as the first character of // both the original message string and the coded message string. // // The program reads input strings and generates and output strings until // an empty line of is input. // // The following algorithm is used to encode each string of text where the // first character of the string is the key character. // // Input: A key character followed by the characters of a string to be encoded. // // Output: The key character, the characters of the encoded message, and a // four-decimal-digit checksum that is the sum modulo 10000 of the // output encoded characters. (The key character is not included // in the checksum.) // // Algorithm: (Used separately on each character) // // 1. Get a character. // // 2. If the character code is zero or greater than 126, terminate // encoding, generate the checksum, and append it to the output. // // 3. If the character code is in the range 1 through 32, output a // caret (^) followed by a second character. Initially, the code // for the second character is the code of the input character plus // the code of the key character. If the resulting code value is // greater than 126, then 32 is added modulo 126 to the initial // value of the code for the second character. // // 4. If the code is anything else, generate the output character(s) // as follows: // 1. Subtract 33 from the character. // 2. Add the code of the key character, modulo 94. // 3. Reflect that value in the range 0 through 93. // 4. Add 33. // 5. Use the result as the output character code. // 6. If the resulting code is the code for the caret character (^), // also output the key character after the generated character....
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This note was uploaded on 03/08/2010 for the course COM SCI 31 taught by Professor Kinsey during the Spring '98 term at UCLA.
- Spring '98