Flow charts
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Flow charts

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Flow charts Document Transcript

  • 1. Introduction to flowchartingAs it was discussed earlier that the computer has no imagination or thinking of its own, every logic or taskthat has to be performed to the computer is detailed. For this purpose, we have to give some instructionsto the computer that is called programming.Programming process:-The set of detailed instructions which group the data processing activities together that are to beperformed by a computer is called programs. The computer programming process is the collection ofthese six phases. 1. Program Analysis: Before making programs, the analysis of the system is done. This includes the inputs that are to be taken, the processing and the outputs that are to be generated. In this phase, it is also checked that if the program worth making. 2. Program Design: In this phase; the program layout is prepared by the system analyst and provided to the programmer. This is done using flowcharts that shows the flow of data, documents etc. very clearly. 3. Program Coding: In this phase, the implementation of flowchart is done using any programming language. For each language, there are separate set of instructions with their respective syntax. Program coding is done in a way that these three objectives are achieved:- simplicity, efficient utilization of storage and least processing time. 4. Program debugging: After completion of program coding, it is compiled and run. During this process, only few errors can be traced. After elimination of these errors, the program is put to use in real necessity. The logical errors (bugs) that arise now are to be removed and this process is known as debugging. 5. Program documentation: Program documentation is done to provide explanation to the end user. This includes:- • Program specification • Program description • The test data that is employed in debugging the program. • The operation manual that lists operating instructions for the operator. • The maintenance documentation that is required to the person who has to make the necessary changes to the program. 6. Program Maintenance: the changes are constantly required in a business system and hence the program is also required to be changed. For this, separate programmers are required that are known as maintenance programmers. Because of this purpose the programs that ire written should be simple and self explanatory.Types of Flow charts:- 1. System outline chart: These charts mainly list the broad aspects of an application like structure, inputs, types of files to processed without regard to any sequence of flow. In these charts we mainly outline the work to be done in an application. 2. System flow chart: These charts represent the logical flow of all aspects of the data processing system in graphical manner. Like in complete application of sales department, to display the logical flow of sales order processing systems and its interlinking with other application, a systems flow chart is prepared. 3. Run flow chart: Since the system flowchart is a collection of several processes, the run flow chart in fact represents the future detailing of any particular process of system flow chart. 4. Program flow chart: These flow charts are the most detailed flow charts and are concerned with actual logical/arithmetic operations on data within CPU & for flow of data to various devices within application. These flow charts are normally directly converted into programs with the help
  • 2. of statements. These flow charts are normally prepared by programmer for graphical solution of any arithmetic and logical problems.Here, mainly we have concern with program flowchart for solving the problem. As we saw thatflowcharting is the part of program design and programs design phase comes after program analysis,hence to dray any flowchart we should first of all do the analysis of the problem for which we want todraw the flowchart. i.e. the input required and the processing that has to be applied to get the desiredoutput.FlowchartDefinition: Flow charts can be defined as pictorial representations of an algorithm by system analysts forplanning the procedure to solve a program. The diagram includes the flow of process, relevant operationsand computations, point of decision and other information which is a part of solution.Algorithm: It is a step-by-step problem solving procedure that can be carried out by a computer. Its mainfeatures include: 1. It should be simple 2. It should be clear 3. It should lead to a unique solution to a problem. 4. It should have finite number of steps to arrive to a solution. Symbols used in a flow charts:- Start/stop Box Represents the beginning or the end of a flow chart Input/ Output Box Represents to accept the input from the user and display the output on the respective devices Processing Box Represents the processing on variables input by the user Decision Box Used for checking the condition and proceeding, based on the value that is returned by the comparisonof the condition either True or False. Flow Lines Represents the flow of controls from one process to another A B Connectors These are used to join two different processes together.
  • 3. General guidelines to prepare Flowcharts:- 1. Listing all requirements in proper logical order and in detail. 2. Must be maid clear, neat and easy to fallow in order to have a good visual impact. 3. Use appropriate standard flowcharting symbols. 4. Make comparison instructions simple. Yes/No type. 5. Avoid intersections of lines, used to depict the flow of logic. 6. Use connectors to reduce the number of flow lines. Connector’s are useful where the flow charts are several pages long. 7. Check that the flowchart is logically correct and complete. This process is technically known as debugging and is done by using suitable test data.Advantages of using flowcharts:- 1. Communication: flowcharts are a good visual aid for communicating the logic of a system, to all concerned. 2. Quicker group of relationship: with the help of flowcharts, the relationship between the procedures can be identified and understood easily. 3. Effective analysis and synthesis: before programming a new system, the analysis is done effectively using flowcharts. In a running system program, flowchart may be used to combine old approaches with the new logics. 4. Efficient coding: with the help of flow chart the program logic can be implemented in any programming language for building up a new system. 5. Orderly debugging: the flowchart also helps in debugging process i.e. it helps in detecting, locating and removing mistakes.Limitations of Flowcharts:- 1. Complex Logic: When the program logic is complex, the flowcharts become lengthy and lack clarity in decision table. 2. Alteration and Modification: If alterations are required, the flowchart may require re-drawing completely. 3. Reproduction: As flowchart symbols cannot be typed, reproduction of flowchart is often a problem. 4. Standardization: Though program flowcharts are easy to follow, they are neither expressed completely in English, nor ere they translated in programming languages.