A flow chart is often used by programmers as a program-planning tool or working process planning for organizing a sequence of steps necessary to solve a problem by a computer. It uses of different symbols to denote different types of instructions. The process of drawing a flowchart for algorithm is often referred to as flow charting.
Flowchart symbols (building blocks):
A typical flowchart from computer science and industrial use may have the following kinds of flowchart symbols or building blocks that are uses as to representing a process are given below with suitable example;
Start and end symbols:
This shape and symbol of flowchart describe where the flowchart start and end. It shows the entry point of flowchart and the exit point. To designate the start of flowchart, designer would fill this shape with words like Start or Begin.
Flowchart Start and Begin symbol
To designate the ending point of the flowchart, this shape is filled with words like End, Exit, or Return.
Flowchart End, Exit, or Return symbol
Usually a flowchart has one starting point. However, a flowchart can have as many ending points as needed. Sometimes start symbol drawn as an oval shape as shown below.
Sometimes it’s represented as circles, ovals or rounded rectangles, usually containing the word “Start” or “End”, or another phrase signaling the start or end of a process, such as “submit enquiry” or “receive product”.
Lines with Arrows:
Flow of control symbol:
A line or an arrow showing data flow that 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.
Users can read a flowchart by following the lines with arrows from symbol to symbol. The lines with arrows determine the flow through the chart. Flowcharts are usually drawn from top to bottom or left to right. Numbering shapes is optional. Numbering is helpful if user have to refer to a shape in a discussion. In reflows user can turn on numbering by clicking on Tools and Number Shapes. Numbering does not determine the flow of control. That is determined by the lines with arrows.
If two lines cross, ignore the perpendicular line and continue following the line to the next shape. If there may be confusion as to the path, user can insert a bridge or crossover, which is a little bump on crossed lines. In reflows, you can insert bridges on crossed lines by clicking on Tools, Global Changes, and Add Crossovers.
Rectangle as process symbol:
In most flowcharts, the rectangle is the most common shape. It is used to show a process, task, action, or operation. It shows something that has to be done or an action that has to be taken. The text in the rectangle almost always includes a verb. For example; “Add 1 to X”; “replace identified part”; “save changes” or similar.
Input and Output Step:
Parallelogram as a input output symbol:
Whenever a user or a process required a direct or indirect input from outside or if it requires producing output then this action is represented as a parallelogram. For example: Get X from the user; display X.
Conditional or decision step:
Rhombus as a decision symbol:
A decision asks a question, answer to the question determines which arrow you follow out of the decision shape, it’s 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. The arrows should always be labeled. For example, in the shape below, if it is cloudy, you follow the arrow down near the word Yes. If it is not cloudy, you follow the arrow to the right near the word no.
More than two arrows can be used, but this is normally a clear indicator that a complex decision is being taken, in which case it may need to be broken-down further, or replaced with the “pre-defined process” symbol.
Connection of different pages (Circle):
Circle as a connector symbol:
If user need to connect to another page or another section of the chart, and can’t draw a line, user can use a circle. User draws the line to the circle and label the circle with a letter. Then place a copy of the circle where user wants the flow to continue. This should be avoided, but sometimes is necessary. Originally the circle was used only to reference another part of the chart and the off page connector, shown later, was used to go to another page. However, the circle is now often used for both.
Example of connector’s symbol:
In Process Mapping the circle represents an Inspection. At an inspection, the quality of the product is evaluated. The flow continues only if the product is approved.
A number of other symbols that have less universal currency, such as:
- A Documentrepresented as a rectangle with a wavy base.
- A Manual inputrepresented by parallelogram, with the top irregularly sloping up from left to right. An example would be to signify data-entry from a form.
- A Manual operationrepresented by a trapezoid with the longest parallel side at the top, to represent an operation or adjustment to process that can only be made manually.
- A Data Filerepresented by a cylinder.
Examples of flow chart: