Explai n the 'Block Codes' and 'Mnemonic Codes' with the help of an example.

Block codes: A range of numbers is partitioned into a desired number of sub ranges and each subrange is allotted to a specific group. In most of the uses of block codes, numbers within a subrange follow sequential coding scheme. For example, Codes Dealer type $\displaystyle 100$-$\displaystyle 199$ Small pump $\displaystyle 200$-$\displaystyle 299$ Medium pump $\displaystyle 300$-$\displaystyle 399$ Pipes Or any other suitable example. Mnemonic codes: A mnemonic code consists of abbreviations as symbol to codify a piece of information ‘PJ’ for Purchase Journal, DDN for Dehradun. These codes can be remembered easily and aids its user in recalling the information it represents. Example: Entering SUB may initiate a computer to subtract.