Open and Closed Hashing in C

Posted on March 17, 2011 at 09:12 C No Comments

Again, I’m under the impression that you’ve done your assignment before coming here. I had this during my postgrad certification. Those were the bloody days that proved that my undergraduate years were nothing but a prelude to hell.

• Open: cells contain pointers to linked lists; collisions and a handful of inputs can be efficiently handled

  /* point each cell to its respective (empty) Stack */
  for(i = 0; i < MAX_VALUE; i++) {
     Stack *s = malloc(sizeof(Stack));
     initStack(s);
     oh->cell[i] = s;
  }
  

• Closed: cells can contain two elements; makes use of a rehashing function to constantly search for an available cell when a collision occurs

  for(i = 0; i < MAX_VALUE; i++) {
     for(j = 0; j < 2; j++) {
        ch->cell[i][j] = 0;
     }
  }
  

Input validation was kinda neglected (and I’m obviously not into adding them right now) so, children, refrain from inputting non-numeric keys, okay?

Hush.zip

Vigenere Cipher in Java

Posted on August 27, 2010 at 18:31 Java 3 Comments

By stumbling upon this page, I presume knowledge on the encryption is already at hand. Otherwise, take a walk first. The program is under the following assumptions:

• User only inputs characters (and spaces!) included in the given alphanumeric set.
• Numeric characters result in uppercase plain/cipher characters.
• Encryption/decryption key cannot have a space.

VigenereCipher.java

private static final char[] alphnum = {
   'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L',
   'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
   'Y', 'Z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'
};