We know that computer is user dependent machine. It doesn't work or think on its own. All the activities of computer system are controlled and processed by the instructions and information provided by the user. These instruction are called commands. Collection of such instruction and the data in a systematic form to solve the problem is called the program.
To solve the problem using computer we have to make some systematic plan of action. Such plan of action can be represented in the systematic order using different tools and technique called the program presentation tools and technique. Popular tools and technique used to represent the programs are flowchart and algorithm.
Algorithm is defined as a set of rules that define how a particular problem can be solved in finite number of steps. In another word, algorithm is a step by step representation of instructions to solve the problem. An algorithm must be composed of a finite set of steps, each of which may require one or more operations.
The good algorithm should have following features:
The step by step solution of a problem in a picture form is known as flowchart. It is one of the most important and oldest techniques to depict an algorithm.
A Flowchart facilitates the computer in following ways:
The basic flowchart symbols are:
According to use and application of the flowchart we have two types of flowcharts: system flowchart and program flowchart.
1. Analyse the input, process, storage and output of the program.
2. Use standard symbols and arrowhead to the direction of flow of data and instructions.
3. We should use easy word which can be easily understood by other programmer.
4. There should be a list of activities inside each symbol.
5. It should express all sections like input, process, logical and output.
6. It should not be any programming language oriented.
An algorithm is a sequence of steps required to solve a particular problem. The concept of algorithm was given by ALKHOWARISMI.
Flowchart is a graphical representation of program solving steps so that it makes clear about the program. The concept of flowchart was given by John Vonn Neuman 1945.
Types of flowchart are:
a) System Flowchart b) Program Flowchart
|System flowchart||Program flowchart|
|1. System flowchart gives complete processing mechanism and cannot be converted into program||1. Program flowchart gives the problem solving method and can be converted into program.|
|Example: Organizational structure of a college.||Example: Problem to calculate area of triangle.|
The common guidelines (properties) of flowchart are:
The flowchart should have only one start and ending points.
Flow lines shouldn't intersect each other.
Flowchart should not contain the programming language.
The flowchart should be neat and clear for the user.
Some of the symbols used in flowchart along with their meanings are listed below:
Two disadvantages of flowchart are:
Step 1 : Start
Step 2 : Read radius and store to R
Step 3 : Assign value of pie to P
Step 4 : Find area and circumference
Step 5 : Display area and circumference
Step 6 : Stop
Step 1 : Start
Step 2 : Read A, B
Step 3 : Assign A to X and B to Y
Step 4 : Divide A by B.
Step 5 : Is remainder zero? If yes, go to step 7.
Step 6 : Assign A to B and B to remainder. And go to step 4
Step 7 : Assign B to HCF
Step 8 : Multiply X and Y and divide by HCF. And assign result to LCM.
Step 9 : Display HCF and LCM
Step 10 : Stop