Flow charts

What is a Flowchart? 

Flowchart is a graphical representation of an algorithm. Programmers often use it as a program-planning tool to solve a problem. It makes use of symbols which are connected among them to indicate the flow of information and processing. 

The process of drawing a flowchart for an algorithm is known as “flowcharting”.

Basic Symbols used in Flowchart Designs

1. Terminal: The oval symbol indicates Start, Stop and Halt in a program’s logic flow. A pause/halt is generally used in a program logic under some error conditions.Terminal is the first and last symbols in the flowchart. 

Input/Output: A parallelogram denotes any function of input/output type. Program instructions that take input from input devices and display output on output devices are indicated with parallelogram in a flowchart. 

Processing: A box represents arithmetic instructions. All arithmetic processes such as adding, subtracting, multiplication and division are indicated by action or process symbol. 

Decision Diamond symbol represents a decision point. Decision based operations such as yes/no question or true/false are indicated by diamond in flowchart. 

Connectors: Whenever flowchart becomes complex or it spreads over more than one page, it is useful to use connectors to avoid any confusions. It is represented by a circle. 

Flow lines: Flow lines indicate the exact sequence in which instructions are executed. Arrows represent the direction of flow of control and relationship among different symbols of flowchart. 

Rules For Creating Flowchart :

A flowchart is a graphical representation of an algorithm.it should follow some rules while creating a flowchart

Rule 1: Flowchart opening statement must be ‘start’ keyword.

Rule 2:  Flowchart ending statement must be ‘end’ keyword.

Rule 3: All symbols in the flowchart must be connected with an arrow line.

Rule 4: The decision symbol in the flowchart cannot be associated with the arrow line.

Advantages of Flowchart:

• Flowcharts are a better way of communicating the logic of the system.
• Flowcharts act as a guide for blueprint during program design.
• Flowcharts help in the debugging process.
• With the help of flowcharts programs can be easily analysed.
• It provides better documentation.
• Flowcharts serve as a good proper documentation.
• Easy to trace errors in the software.
• Easy to understand.
• The flowchart can be reused for inconvenience in the future.
• It helps to provide correct logic.

Disadvantages of Flowchart:

• It is difficult to draw flowcharts for large and complex programs.
• There is no standard to determine the amount of detail.
• Difficult to reproduce the flowcharts.
• It is very difficult to modify the Flowchart.
• Making a flowchart is costly.
• Some developers think that it is a waste of time.
• It makes software processes low.
• If changes are done in software, then the flowchart must be redrawn

Example : Draw a flowchart to input two numbers from the user and display the largest of two numbers