C

                                                                    INTRODUCTION

Computer 

 Basically it is a fast calculating machine which is now a days used for variety of uses ranging from house hold works to space technology. The credit of invention of this machine goes to the English Mathematician Charles Babbage.  

ASCII Codes: 

 American standard code for information interchange. These are binary codes for alpha numeric data and are used for printers and terminals that are connected to a computer systems for alphabetizing and sorting.

 

Operating Systems

 

 The set of instructions which resides in the computer and governs the system are called operating systems, without which the machine will never function.  They are the medium of communication between a computer and the user. DOS, Windows, Linux, Unix etc are Operating Systems.

Languages.

  These programs facilitate the users to make their own programs. User’s programs are converted  to machine oriented and  the computer does the rest of works.

 

Application Programs

     These programs are written by users for specific purposes. 

Computer Languages

 

           They are of three types –

 

1                 Machine Language ( Low level language )

2                 Assembly language  ( Middle level language )

3                 User Oriented language ( Higher level language )

 

 Machine language depends on the hard ware and  comprises of 0  and 1 .This is tough to write as one must know the internal structure of the computer. At the same time assembly language makes use of English like words and symbols. With the help of  special programs called Assembler, assembly language is converted to machine oriented language. Here also a programmer faces practical difficulties. To over come this hurdles  user depends on Higher level languages, which are far easier to learn and use. To write programs in higher level language, programmer need not know the characteristics of a computer. Here he uses English alphabets, numerals and some special characters. 

 Some of the Higher level languages are FORTRAN, BASIC, COBOL, PASCAL, C, C++, ADA etc. We use C to write programs. Note that Higher level languages  can not directly be followed by a computer. It requires the help of certain soft wares to convert it into machine coded instructions. These soft wares are called Compiler, Interpreter, and Assembler. The major difference between a compiler and an interpreter is that  compiler compiles the user’s program into machine coded by reading the whole program at a stretch where as Interpreter translates the program by reading it line by line.

C  and BASIC  are an Interpreter where as FORTRAN is a  PROGRAMMING METHODOLOGY

 

A computer is used to a solve a problem.

Steps

1               Analyze the problem

2               Identify the variables involved

3               Design the solution

4               Write the program

5               Enter it into a computer

6               Compile the program and correct errors

7               Correct the logical errors if any

8               Test the program with data

9               Document the program

 

Algorithms

          Step by step procedure for solving a problem is called algorithm.

 

 

 

 

 

Example 

To make a coffee 

                    Step1: Take proper quantity of water in a cooking pan

                         Step2: Place the pan on a gas stow and light it

                        Step3: Add Coffee powder when it boils

 Step4: Put out the light and add sufficient quantity of sugar and milk

                        Step5: Pour into cup and have it.

To add two numbers

                        Step1: Input the numbers as x, y

                        Step2: sum=x + y

                         Step3: print sum

 

For a better understanding of an algorithm, it is represented pictorially. The pictorial representation of an algorithm is called a Flow Chart. For this certain pictures are used.