Flowchart

From Free net encyclopedia

Image:LampFlowchart.png 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.

Many humorous flowcharts exist, e.g. one that outlines how to pass the blame if something goes wrong.

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, such as Visio, OpenOffice.org Draw, Dia, SmartDraw, and OmniGraffle.

Programs have been written to create flowcharts directly from computer program source.

1 History of use
2 Symbols used in flowcharts
3 Creating flowcharts on a computer
4 See also
5 External links

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History of use

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 begun to supplant the use of flowcharts. With the widespread adoption of such ALGOL-like computer languages as Pascal, textual models like pseudocode have been used more often to represent algorithms. In the 1990s Unified Modeling Language began to synthesize and codify these modeling techniques.

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Symbols used in flowcharts

A typical flowchart from older Computer Science textbooks may have the following kinds of symbols:

Start and end symbols, represented as ovals or rouned rectangles, usually containg the word "Start" or "End".
Arrows, showing what's called "flow of control" in computer science. An arrow coming from one symbol and ending at another symbol represents that control passes to the symbol the arrow points to.
Processing steps, represented as rectangles. Example: Add 1 to X.
Input/Output, represented as a parallellogram. Examples: Get X from the user; display X.
Conditional, represented as a diamond (rhombus). These typically contain a Yes/No question or True/False test. This symbol is unique in that it has two arrows coming out of it, usually from the bottom point and right point, one corresponding to Yes or True, and one corresponding to No or False.

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.

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Creating flowcharts on a computer

There are various packages for creating flowcharts, according to different standards. The most common is UML, for which there are abundant packages for various platforms. See UML article for 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) and OpenOffice.org (Draw-module or CustomShapes) both 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.

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.

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