flowchart - Symbols, Software, Examples

A diagrammatic representation of a sequence of events. In the computing context, a data flowchart describes the overall operations in a complete data-processing system, such as an accounting system, without giving specific details of the individual computer programs; a program flowchart describes the sequence of operations within the program. There are recognized symbols to indicate the various types of operation.

A flowchart (also spelled flow-chart and flow chart) is a schematic representation of an algorithm or a 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.

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.

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.

Symbols

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

Start and end symbols, represented as lozenges, ovals or rounded rectangles, usually containing the word "Start" or "End", or another phrase signalling the start or end of a process, such as "submit enquiry" or "receive product". An arrow coming from one symbol and ending at another symbol represents that control passes to the symbol the arrow points to. A Manual operation represented by a trapezoid with the longest parallel side upmost, to represent an operation or adjustment to process that can only be made manually. A Data File represented by a cylinder

Flowcharts may contain other symbols, such as connectors, usually represented as circles, to represent converging paths in the flow chart. These are useful to represent an iterative process (what in Computer Science is called a loop).

A flowchart is described as "cross-functional" when the page is divided into different "lanes" describing the control of different organisational units.

Software

Manual

There are various packages for manually creating flowcharts, according to different standards. 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.

You can also create Flowcharts directly in Excel (useful for printing in large papers) and in Powerpoint (useful for presentations).

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. 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.

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. }

There exist also various MediaWiki Extensions 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! However, this flowchart would be difficult to program directly into a computer programming language since most programming languages branch on "yes" or "true" and continue on "no" or "false". Further, the flowchart represents "a loop and a half" -- a situation discussed in introductory programming textbooks that requires either a duplication of a component (to be both inside and outside the loop) or the component to be put inside of a branch in the loop.

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.