n the range of 0 to 9999 we can truncate the high-order 5 to yield 5354 as our relative address. Try using another base to calculate the relative address.Mid-SquareMid-square randomizing scheme involves the extraction from the key the middle n digits and then squaring them to form the relative address. Again the excess high-order digit can be truncated to make the value fit the range. For the key value 29615834, the middle three digits (158) could be extracted and squared, resulting in 24964 as the relative address. Since this number is too large to be in the range value, the high-order digit is extracted and the relative address now becomes 4964 for the recored with the key value of 29615834. This form of randomizing scheme works well if the key does not contain a lot of leading or trailing zeros.TECHNIQUES FOR HANDLING COLLISIONSThere are several ways for handling collisions and synonyms. They can be classifiied as open addressing and chaining. The methods described are as follows: 1.Linear Probing 2.Two-Pass File Creation with Hashing 3.Separate Overflow Area 4.Double Hashing 5.Synonym Chaining 6.Bucket Addressing Linear ProbingIn linear probing, files are scanned sequentially as a circular file and the synonym, which caused the collision, is stored in the nearest available space to the hashed address. That is if we use a hashing function to calculate the relative address for the words ‘AS’ and ‘HIS’, and these two words happens to have the same relative address, say 18, the first word ‘AS’ will be stored in the relative address 18, the second word ’HIS’ will be stored in next available position that is empty. It could be position 19 or 20, in general it could be i+1, i+2, ..., n, 1, 2, ..., i-1. Where i in this case is position 18, and n is the total number of positions available. Two-Pass File Creation with HashingThis technique is an improvement on the linear prob...
