UNIT-1

1.      Define a Computer?

ANS:  A computer is an electronic device capable of manipulating numbers and symbols under the control of a set of instructions known as computer program.

2.       List out the various components of the computer?

ANS:

1. Arithmetic and Logical unit

2. Memory unit

3. Control unit

4. Input unit

5. Output unit

3.      List out the various componrnts of CPU?

The CPU (Central Processing Unit) Consists of.

a. ALU (Arithmetic Logic Unit)

b. CU (Control Unit)

c. MU (Memory Unit)

a. The Control Unit Controls all the activities of the Computer. It sends commands and control signals and finds the sequence of instruction to be executed.

b. Memory Unit is the place where all input data and results are stored. Computer memory is also available in the form of Random Access Memory (RAM)

c. ALU Consists of CKTs for arithmetic operations(+,-,*,/) and logical operations (<,>,>=,<=,==,!=)

4.      RAM : It is a temporary storage medium in a computer. The data to be processed by the computer are transferred from a storage devices or a keyboard to RAM results from a executed program are also stored in RAM. The data stored will be erased when the computer is off.

5.      ROM (Read only Memory) : This is a non-volatile or data storage medium which stores start up programs (operating systems). This essentially stores the BIOS (Basic Input Operating System)

6.      Write notes on programming languages?

Languages of different Generation Computer.

1. First – Generation Language : All the instructions are in the binary form and are referred to as machine level or low level language (LLL). It is very difficult to read the instructions written in binary  Eg : 00110101011101110001, 101100001010101

2. Second – Generation Language: all the instruction are in the forms of mnemonics. The symbolic instruction language called as Assembly Language. All the symbolic instructions are converted into binaries with the help of translator called Assembles. Source Program Eg : ADD A, B, R,

             3. Third – Generation Language : These are written in English with symbols and digits. Then 

                  are known as High level language (HLL). common high level languages are c,c++, 

                  COBOL, BASIC, FORTRAN, PASCAL, etc.

7.       ASCII (American Standard Code For Information Interchange) is commonly used for translation of source Program into object program

8.      Features of “C” Language :

1. It is robust language because of rich set of binary in – function

2. It is efficient and fast because of its variant data-types and powerful operation.

3. It is highly Portable i.e., programs written in one computer can be run on another

4. It is well suited for structure program, thus allows the user to think about the problem in the terms of functional blocks.

5. Debugging, testing and maintenance is easy

6. ability to extend itself, we can continuously add our own functions to the program.

9.      Complier : This reads the entire source program and converts it to the object code. It provides error not of one line, but errors of the entire program. It executes as a whole and it is fast

10.  Interpreter : It reads only one line of a source program at a time and converts it into an object code. In case of errors/same will be indicated instantly. It executes line by line and it is slow

11.  Linker is a function which links up the files that an present in the operating system, it also links the files for the hardware and makes the system ready for executing.

12.  Preprocessor : This is a program, that processes the source program before it is passed on to the compiler. The program typed in the editor is the source code to the preprocessor, then it passed the source code to the compiler. It is not necessary to write program with preprocessor & activity Preprocessor directories are always initialized at the beginning of the program. it begins with the symbol (#) hash. It place before the main() function

Eg: # include <station>  # define PI 3.14

13.  Write notes on C character Set?

Character Set : The characters that can be used to form words and expressions depends upon the computer to which the program is run

            The Characters in C are

1. Letters A-X, a-z, both upper and lower

2. Digits 0-9

3. Special character, +,-,*,”,;,./,

4. which spaces newline, horizontal tab;,carriage return ,blank space

14.  “C” Tokens: Individual words and punctuation marks are characters. In a “C” program the smallest individual units are known as “C” tokens. It has 6types of token‟s.

15.  Keywords : Keywords are reserved words by compiler. Keywords are assigned with fixed meaning and they cannot be used as variable name. No header file is needed to include the keywords. There are 32 keywords Eg : auto, break, double, int, float.

16.  Identifiers : These are the names of variables ,functions and arrays, these are the user defined names Eg : # define NUM 10 # define A 20 “NUM”, “A” are user – defined id

17.  Constants : constants in “C” are applicable to the values which not change during the execution of a program.

18.  Integer Constants : Sequence of numberr 0-9 without decimal points, fractional part or any other symbols. It requires two or four bytes, can be +ve, -ve or Zero the number without a sign is as positive. Eg: -10, +20, 40

19.  Real Constants : Real constants are often known as floating constants. Eg: 2.5, 5.521, 3.14 etc

20.  Character Constants Single character const : A single character constants are given within a pair of single quote mark. Eg : „a‟, „8‟, etc.

21.  String Constant : These are the sequence of character within double quote marks Eg : “Straight” “India”, “4”

22.  Variables : This is a data name used for storing a data, its value may be changed during the execution. The variables value keep‟s changing during the execution of the program Eg : height, average, sum, etc.

23.  Data types: C language is rich in data types ANSI – American National Standard Institute ANSI C Supports Three classes of data types.

1. Primary data type(fundamental)

2. Derived data types

3. User defined data types

24.  All “C” compiler supports 5 fundamental data types

1. Integer (int)

2. Character (char)

3. floating point (float)

4. double-precession (double)

5. void

25. 

26.  Operator: An operator is a symbol that tells the Computer to perform certain mathematical or logical manipulations.

27.  Expression: An expression is a sequence of operands and operators that reduces to single value Eg: 10+25 is an expression whose value is 35

28.  Types of Operators?

ANS:  C operators can be classified into a no. of categories. They include:

1. Arithmetic

2. Relational

3. Logical

4. Assignment

5. Increment and Decrement

6. Conditional

7. Bitwise

8. Special

29.  Arithmetic Operators: C provides all the basic arithmetic operators, they are +, -, *, /, % Integer division truncates any fractional part. The modulo division produces the remainder of an integer division. Eg: a + b a – b a * b -a * b a / b a % b

30.  Relational Operator: These are the operators used to Compare arithmetic, logical and character expressions.the value of a relational express is either one or zero .it is 1 if one is the specified relation is true and zero if it is false For eg: 10 < 20 is true 20<10 is false

31.  Logical operator : Logical Operators are used when we want to test more than one condition and make decisions. here the operands can be constants, variables and expressions Logical operators are &&, ||, ! Eg: a > b && x = = 10 Logical or compound relational Expression Truth Table && ||, !

32.  Assignment Operator: Used to assign the result of an expression to a variable. „= „is the assignment operator. In addition C has a set of „short hand‟ assignment operators of the form

Var Op = Exp

33.  Increment and Decrement Operators: ++ and - - The Operator + + adds 1 to the operand while -- subtracts 1, Both are unary operators Eg : ++x or x ++ == > x+=1 == > x=x+1 . -- x or x- - == > x-=1 == > x=x-1

34.  A Profix operator first adds 1 to the operand and then the result is assigned to the variable on left. A postfix operator first assigns the value to the variable on the left and the increments the operand. Eg: 1) m = 5; 2). m = 5 y = ++m; y = m++ O/P m =6, y=6 m=6, y=5

35.  Conditional operator: is used to check a condition and Select a Value depending on the Value of the condition. Variable = (condition)? Value 1 : Value 2: If the Value of the condition is true then Value 1 is e valued assigned to the varable, otherwise Value2. Eg: big = (a>b)? a:b;

36.  Bitwise operator : are used to perform operations at binary level i. e. bitwise. these operators are used for testing the bits, or Shifting them right or left . These operators are not applicable to float or double. Following are the Bitwise operators with their meanings. Operator Meaning & Bitwise AND | Bitwise OR ^ Bitwise Exclusive – OR << Left Shift >> Right Shift ~ Complement

37.  consider a = 13 & b = 6 as 8 bit short int (1byte) << Left Shift a = 13 Binary 00001101 b = 6 00000110 Consider a << 2 which Shifts two bits to left , that is 2 zeros are inserted at the right and two bits at the left are moved out. 00001101 Moved 00110100 Finally the result is 00110100 . Deci 52 (13x4)

38.  WAP to illustrate the use of size of operator main ( ) { int x = 2; float y = 2; printf (“ in size of ( x ) is %d bytes “, sizeof ( x )); printf (“ in size of ( y ) is %d bytes “, sizeof ( y )); printf (“ in Address of x = % u and y = % u “, & x, & y); } o/p sizeof ( x ) = 2 sizeof ( y ) = 4

39.  sizeof operator : is used to find the on. of bytes occupied by a variable / data type in computer memory. eg : sizeof (float) returns 4 int m, x [ 50 ] sizeof (m) returns 2 sizeof ( x ) returns 100 ( 50 x 2 )

40.  comma operator : can be used to link the related expressions together. A comma- linked: list of expressions are evaluated left to right and the value of right-most exp is the value of combined expression.

Eg : value = ( x = 10, y = 5, x = y)

41.  Associativity : when there are more than one operator with same precedence [ priority ] then we consider associativity , which indicated the order in‟ which the expression has to be evaluated. It may be either from Left to Right or Right to Left. eg : 5 * 4 + 10 / 2 1 2 = 20 + 5 3 =25

42.  Type Casting: Normally before an operation takes pace both the operands must have the same type. C converts One or both the operands to the appropriate date types by “Type conversion”. This can be achieved in 3 ways.

43.  Implicit Type conversion : In this the data type /Variable of lower type (which holds lower range of values or has lower precision ) is converted to a higher type (which holds higher range of values or has high precision). This type of conversion is also called “promotion”

44.  Assignment Type Conversion: If the two Operands in an Assignment operation are of different data types the right side Operand is automatically converted to the data type of the left side.

45.  Explicit Type Conversion: When we want to convent a type forcibly in a way that is different from automatic type conversion, we need to go for explicit type conversion. (type name) expression; Type name is one of the standard data type. Expression may be a constant variable Or an expression this process of conversion is called as casting a value. Eg: x = (int) 7.5

46.  Escape Sequences with their ASC|| values Escape Sequence Use ASC|| Value \n New line 10 \b Backspace 8 \f Form feed 12 \‟ Single Quote 39 \\ Back slash 92 \o Null 0 \ t Horizontal tab 9 \ r Carriage return 13 \ a Alert 7 |? Question marks 63 \“ Double Quote 34

47.  a). scanf ( ) function is used to read values using key board. It is used for runtime assignment of variables. The general form of scanf( ) is scanf(“format String “ , list_of_addresses_of_Variables ); The format string contains - Conversion specifications that begin with % sign Eg: Scan f(“ %d %f %c”, &a &b, &c) „&‟ is called the “address” operator. In scanf( ) the „&‟ operator indicates the memory location of the variable. So that the Value read would be placed at that location.

48.  printf( ): function is used to Print / display values of variables using monitor: The general form of printf( ) is printf(“control String “ , list_of_ Variables );

- Characters that are simply printed as they are

- Conversion specifications that begin with a % sign

- Escape sequences that begin with a „\‟ sign.

      49.  A computer system consists of hardware and software.

Computer hardware is the collection of physical elements that comprise a computer system.

Computer software is a collection of computer programs and related data that provides the instructions for a computer what to do and how to do it. Software refers to one or more computer programs and data held in the storage of the computer for some purposes.

50.

 1. Operating System

The Operating System (OS) is an interface between the compute software and hardware. The most popular and latest operating systems include Windows XP, Mac, UNIX, Linux, Windows Vista, etc.

2. Application Software

The application software is widely used for accomplishment of specific and precise tasks which is a step ahead than the basic operations or running of the computer system. The application software includes printing documents, and permitting access to internet for web and video conferencing activities. The Application software indirectly does the interaction with the machine to perform all these functions.

3. System Software

System software directly interacts with computer hardware. Some of the examples are the device drivers for CPU, Motherboard, Mouse, Printer, Keyboard, etc. The system software takes the responsibility of control, integration and managing individual hardware machine of the computer.

51.

Algorithm:

An algorithm is a description of a procedure which terminates with a result. Algorithm is a step-by-step method of solving a problem.

Properties of an Algorithm:

1) Finiteness: - An algorithm terminates after a finite numbers of steps.

2) Definiteness: - Each step in algorithm is unambiguous. This means that the action specified by the step cannot be interpreted (explain the meaning of) in multiple ways & can be performed without any confusion.

3) Input: - An algorithm accepts zero or more inputs

4) Output:- An algorithm should produce at least one output.

5) Effectiveness: - It consists of basic instructions that are realizable. This means that the instructions can be performed by using the given inputs in a finite amount of time

52.

Flowchart:

A flowchart is a graphical or pictorial representation of an algorithm.

Each step in the process is represented by a different symbol and contains a short description of the process step. The flow chart symbols are linked together with arrows showing the process flow direction.

53.

54.

Program Development Steps:

1. Statement of Problem

a) Working with existing system and using proper questionnaire, the problem should be explained

clearly.

b) What inputs are available, what outputs are required and what is needed for creating workable

solution, should be understood clearly.

2. Analysis

a) The method of solutions to solve the problem can be identified.

b) We also judge that which method gives best results among different methods of solution.

3. Design

a) Algorithms and flow charts will be prepared.

b) Focus on data, architecture, user interfaces and program components.

4. Implementation

The algorithms and flow charts developed in the previous steps are converted into actual programs in the high level languages like C.

55.

General Structure of a C program:

/* Documentation section */

/* Link section */

/* Definition section */

/* Global declaration section */

main() { Declaration part

Executable part (statements) }

/* Sub-program section */

Ø The documentation section is used for displaying any information about the program like the purpose of the program, name of the author, date and time written etc, and this section should be enclosed within comment lines. The statements in the documentation section are ignored by the compiler.

Ø The link section consists of the inclusion of header files.

Ø The definition section consists of macro definitions, defining constants etc,.

Ø Anything declared in the global declaration section is accessible throughout the program, i.e. accessible to all the functions in the program.

Ø main() function is mandatory for any program and it includes two parts, the declaration part and the executable part.

Ø The last section, i.e. sub-program section is optional and used when we require including user defined functions in the program.

56.

Unformatted I/O functions:

1.getchar():Used to read a character

2.putchar():Used to display a character

3.gets():Used to read a string

4.puts():Used to display a string which is passed as argument to the function