Flowchart...

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Question: What is Flowchart?
Answer: A flowchart is a pictorial representation of an algorithm. It is often used by programmers as a program-planning tool for organizing a sequence of steps necessary to solve a problem by a computer. It uses boxes of different shapes to denote different types of instructions. The actual instructions are written within these boxes using clear and concise statements. These boxes are connected by solid lines having arrow marks to indicate the flow of operation, that is, the exact sequence in which the instructions are to be executed. The process of drawing a flowchart for an algorithm is often referred to as flowcharting.
Why Use Flowcharts?
Normally, an algorithm is first represented in the form of a flowchart, and the flowchart is then expressed in some programming language to prepare a computer program. The main advantage of this two-step approach in program writing is that. while drawing a flowchart, a programmer is not concerned with the details of the elements of programming language. Hence, he/she can fully concentrate on the logic of the procedure.
               Experienced programmers, sometimes, write programs without drawing the flowchart. However, for beginner, it is recommended that a flowchart be drawn first to reduce the number of errors and omissions in the program. A flowchart often serves as a document for the computer program, and is very useful during the testing of the program, and while incorporating further modifications in the program.
Need for Flowchart Symbols
A flowchart uses boxes of different shapes to denote different types of instructions. The communication of program logic through flowchart is made easier by the use of symbols, which have standardized meaning. This is because as long as everyone uses the same basic shapes, others can readily interpret the logic. For example, a diamond always means a decision. Hence, when a programmer looks at a flowchart, he/she can easily identify the decision points, because all the indicated all the indicated by a diamond box.
Basic Flowchart  Symbols
Only a few symbols are needed to indicate the necessary operations in a flowchart. These basic flowchart symbols have seen standardized by the American National Standards Institute ( ANSI). They are shown in figure, and their functions are discussed below.

  1. Terminal- The terminal symbol is used to indicate the beginning(start), end (stop) and pause(halt) in the program logic.
  2. Input/Output- The input/output symbol is used to denote any function of an input/output device in the program.
  3. Processing- A processing symbol is used in a flowchart to represent arithmetic and data movement instructions.
  4. Decisions- The decision symbol is used in a flowchart in a flowchart to indicates a point at which a decision has to be made, and a branch to one of two or more alternative points is possible 
  5. Flow lines- Flow lines with arrowheads are used to indicate the flow of operation, that is, the exact sequence in which the instructions are to be executed.
  6. Connectors- Whenever a flowchart becomes complex enough that the number and direction of flow lines is confusing or it spreads over more than one page.   

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