Advantage of Flowchart (a) They are an aid to problem definition and writing program. They help to simplify the logic of a program or process. (b) They are more complete than decision tables for example they include start and end routines and illustrate program loops (c) They can be used to test whether a program logic works, by running through the flowchart with ‘mock data’ to see if it will be processed as intended. (d) They can be included in the specification of the program working papers, so that if there is any requirement in the future to check or amend the program the flowchart will indicate to other programmers the logic of processing as seen by the program written. Disadvantages of Flowchart (a) Complicated processing might required flowcharts that stretch on to several pages. (b) They are not easy to amend. Alterations might involve a complete re-drawing of the flowchart, which could be a time consuming task. (c) They tend to produce a badly structured program design. The logic shown in flowchart is rarely the best or most efficient logic for writing a program, and if a programmer uses flowcharting, his program is likely to be unnecessarily long. Nowadays, professional programmers do not use flowcharting for this reason. STRUCTURED PSEUDO CODES This is a design tool that describes the program tasks in a highly detailed narrative form. This method use English as the language but severely limits the available vocabulary and tries to follow the layout and logical operation of a computer program. Because structured pseudo codes appear to be fairly literal translations of programs, they closely resemble the finished product Structure Pseudo codes has the following features: (a) It is more like spoken English than normal programming language-COBOL, BASIC and so is easily for programmers and non-program to understand. (b) It is much more limited than normal speech, as it has to follow a strict logical order. (c) There is a variety of conventions for writing it. Structure pseudo code uses keywords (e.g. IF, COMPUTE) which by some conventions, are written in capital and have a precise logical meaning in the context of the narrative. There are three basic logical structure. „h SEQUENCING „h SELECTION „h REPETITION SEQUENCING INSTRUCTION Example: MULTIPLY hours worked by Pay rate to get Gross Pay Computation of Gross pay in a program. GET Master record Retrieving Master records from a file for the employee reference. ADD 1 To Counter Counting records. SELECTION INSTRUCTION Most programs offer a number of ‘choices’ where the consequent action depends on the choices being made in structured English. A decision follows this structured. Example, a coy offers discount to trade customers only. How would this be expressed in structured pseudo code. IF THEN ELSE So IF the Customer is a trade Customer THEN give10% ELSE (Customer is not trade customer) SO no discount given. Sometimes, decisions are more complicated. Assume that the Company only offers a 10% discount to trade Customers who have been customer for over one year, but other trade customers receive a 5% discount IF the Customer is a trade Customer IF Customer is over 1 year THEN 10% discount given ELSE 5% discount given Else (Customer not a trade Customer) SO no discount given One particular type of decision is a CASE statement which is an alternative to the IF-THENELSE- SO structure outline above, which is satisfactory for making relatively simple decisions, but can become unwisely when the decision becomes complex. For example, we could have expressed the trade credit policy as follows. ENDIF ends the CASE statement. Kindly visit luckyfemonline.ucoz.org for more updates
Posted on: Wed, 21 Aug 2013 22:42:18 +0000