|
A flowchart (also spelled flow-chart and flow chart) is a schematic representation of a process. They are commonly used in business/economic presentations to help the audience visualize the content better, or to find flaws in the process. The flowchart is one of the seven basic tools of quality control, which include the histogram, Pareto chart, check sheet, control chart, cause-and-effect diagram, flowchart, and scatter diagram. See Quality Management Glossary. Examples include instructions for a bicycle's assembly, an attorney outlining a case's timeline, diagram of an automobile plant's work flow, the decisions to be taken on a tax form, et cetera. Generally the start point, end points, inputs, outputs, possible paths and the decisions that lead to these possible paths are included. Flow-charts can be created by hand or manually in most office software, but lately specialized diagram drawing software has emerged that can also be used for the purpose. See below for examples. Nassi-Schneiderman diagrams are (almost) isomorphic with flowcharts. Everything you can represent with a Nassi-Schneiderman diagram you can also represent with a flowchart. For flowcharts of programs, just about everything you can represent with a flowchart you can also represent with a Nassi-Schneiderman diagram. The exceptions are things like goto, and the C programming language loop break and continue statements.
History Flowcharts were used historically in electronic data processing to represent the conditional logic of computer programs. With the emergence of structured programming and structured design in the 1980s, visual formalisms like data flow diagrams and structure charts began to supplant the use of flowcharts in database programming. With the widespread adoption of such ALGOL-like computer languages as Pascal, textual models like pseudocode have been used more and more often to represent algorithms. In the 1990s Unified Modeling Language began to synthesize and codify these modeling techniques. Today, flowcharts are one of the main tools of business analysts and others who seek to describe the logic of a process in a graphical format. Flowcharts and cross-functional flowcharts can commonly be found as a key part of project documentation or as a part of a business process document. Flowcharts are widely used in education, clinical settings, service industries and other areas where graphical, logical depiction of process is helpful. Symbols A typical flowchart from older Computer Science textbooks may have the following kinds of symbols: Flowcharts may contain other symbols, such as connectors, usually represented as circles, to represent converging paths in the flow chart. Circles will have more than one arrow coming into them but only one going out. Some flow charts may just have an arrow point to another arrow instead. These are useful to represent an iterative process (what in Computer Science is called a loop). A loop may, for example, consist of a connector where control first enters, processing steps, a conditional with one arrow exiting the loop, and one going back to the connector. Off-page connectors are often used to signify a connection to a (part of a) process held on another sheet or screen. A flowchart is described as "cross-functional" when the page is divided into different "lanes" describing the control of different organisational units. A symbol appearing in a particular "lane" is within the control of that organisational unit. This technique allows the analyst to locate the responsibilty for performing an action or making a decision correctly, allowing the relationship between different organisational units with responsibility over a single process. Manual There are various packages for manually creating flowcharts, according to different standards. The most common is UML, for which there are abundant packages for various platforms. See UML article for a list. The creation of simple flowcharts on a computer is fairly easy with any vector-based drawing program, but Microsoft Word (versions 97 through 2003), OpenOffice.org Draw, EDraw Flowchart Software, Inkscape, ConceptDraw and SmartDraw have specialized tools for making consistent charts. When in Microsoft Word, enable the Drawing toolbar and click Autoshapes then Flowcharts and finally on the appropriate shape you would like. Right-click on a shape and then click Add Text to do so. The Arrow or Line tool is used to manually draw links. The connectors are not available in Word 97 - so lines will not remain connected to objects if they are moved. You can also create Flowcharts directly in Excel (useful for printing in large papers) and in Powerpoint (useful for presentations). The functions in these programs are much the same as the Word functions. When in OpenOffice.org, enable the Drawing toolbar which has a flow-out menu for Flowcharts since version 2.0, which can do roughly the same as Word. When in OpenOffice.org Draw, enable the Flowchart palette and click a shape to add it in. Double-clicking a shape will add text to it within appropriate boundaries. Connections can be automatically made between shapes using Connectors and Glue Points - click on the Connector arrow to see a selection of them before dragging from a Glue Point on a shape to another. Draw will maintain the link and automatically redraw the connector if you resize or move any shape. Creating flowcharts can also be done with Microsoft Visio, part of the Microsoft Office Suite of applications. Automatic Various software packages exist that can create flowcharts automatically, either directly from source code, or from a flowchart description language: For examples, Graph: Easy, a Perl package, takes a textual description of the graph, and turns it into various output formats like HTML, ASCII or SVG. The example graph at the top of the page and listed below would be described like the text shown below. The automatically generated SVG output is shown on the right:
There exist also various to incorporate flowchart descriptions directly into wiki articles, this is then automatically turned into the desired output format. Examples A flowchart for computing factorial N (N!) Where N! = 1 Since computer programming languages do not contain all of the constructs that can be created by the drawing of flowcharts, they do not often help new programmers learn the concepts of logical flow and program structure. To try writing flowcharts for computer programs, an on-line applet for iconic programming is available that limits the flowchart components and connections to those that can be directly converted into any programming language. (Note: click on the yellow square to begin.) See also | ||||||||
|
| |||||||||
 |
|
| |