Algorithm  pseudo code and flow  charts

Algorithm:   before  writing  the program  the programmer must understand  the problem  for which are  program is to  be written. Then  algorithm can be  written. An algorithm is the step  wise  program  definition written  in simple  and precise language  in which  the large  problems  is broken  into unbreakable  steps.  So that  each step can be easily  converted into programming  statement. For writing  the algorithm  knowledge of computer language is not required . an  algorithm has followings  features.

a.Finiteness : must  terminate  after a fixed number of steps.

b.Definiteness -  each step must be  precisely defined.

c.Effectiveness - all operations used in  algorithm should be the  basic  operations and  can be  converted  into  programming  instructions directly.

For  example  if we  want to write  a program  to add   two  numbers.  The algorithm for it  which is independent  of any  programming  language  may be  written  as follows:

Algorithm to add  two  numbers:

a.Read  first  number.

b.Read  second number.

c.Add numbers and  save the sum.

d.Display results .

Pseudo code :  An  algorithm  may be  written  in simple  language  as initially we may not  know  which  programming language will be  used to  implement the  algorithm. Some  times  it may  be difficult to convert an algorithm into the  computer  program. Hence an  intermediate language, which is in  between  teh algorithm and actual programming language is used. This language is called pseudo code.

For example  the algorithm written above to add two  numbers may be  converted to the  pseudo  code  as follows if programming is to  be done  in assembly  language of 8085 .

A-FIRST NO

B-SECOND NO

A-A+B

DISPLAY PORT  - A (SUM)

Flow chart : flow  chart is  the  graphical  representation of the algorithm which  shows the flow of  program  execution. It uses  various  symbols  to represent different  processors. The  symbols which  are used  in the book  are explained  below.