Saturday, June 8, 2013

Project Work of Computer

 Project Work
Of
Computer

1.                    Define Operator. List its types with examples.
Þ     Operators are symbols, which are used for mathematical calculations, logical and string operations.  Its   types with examples are as follow:
·         Arithmetic operators:
E.g.: +, -, *, /, \, ^ and MOD.
Use: PRINT 4+5
·         Relational operators:
E.g.: =, <>, <, >, <= and >=
Use: PRINT 6>=5
·         Logical operators:
E.g.: AND, OR and NOT
Use: PRINT 6>5 OR 5>6
·         String operators:
E.g.: +
Use: PRINT A$ + B$

2.            Define Operand. Explain with example.
Þ     Operands may be constant values or variables on which mathematical and logical operations take place.  For example: In the following expression,
S = 4 / 2
/ is operator, and
4 and 2 are operands.

3.         Define Expression. List its types with examples.
Þ     An expression can be a string or numeric constant, a variable or a combination of constants and variables with operators.  Its types with examples are as follows:
·         Arithmetic expression
E.g.:
PRINT 7 * 6 + 5
Z = (X^2) + (Y^3)
·         Logical expression
E.g.:
PRINT 5>6
PRINT 3<4
·         String expression
E.g.:
PRINT A$ + B$
PRINT Kathmandu $ + Nepal$ 

4.      What is Arithmetic Operator? Explain with examples.
Þ     Arithmetic or mathematical operators are symbols, which are used for mathematical operators which assign the result of an arithmetic expression to a variable or displays on the monitor. For example: +, -, *, /, \, ^ and MOD.

5.      Discuss about Operator Precedence.
Þ     In the presence of more than one operator in QBASIC, QBASIC follows a certain order for performing the operations. The order in which the QBASIC performs the operation is known as operator precedence or hierarchy of operations.

The operator precedence in QBASIC is:
·         ()
·         ^
·         - (negative)
·         * /
·         \
·         MOD
·         +,-
·         =
·         <> 
·         < 
·         <=
·         > 
·         >=
·         NOT
·         AND
·         OR

6.      What is Logical Operator? Explain with examples.

Þ      Logical operators are symbols, which are used to combine two or more logical or relational expressions and returns a single ‘true’ or ‘false’ value. For example: AND, OR and NOT.

7.      What is Relational Operator? Explain with examples.
Þ     Relational operators are symbols, which are used in relational or logical expressions. For example: =, <>, <, >, <= and >=.

8.      Show the truth table of AND, OR and NOT operator.
Þ     The truth table are as follows:
·         For AND operator:

Condition
Operator   (AND)
Condition
Result
True (-1)
AND
True (-1)
True (-1)
True (-1)
AND
False (0)
False (0)
False (0)
AND
True (-1)
False (0)
False (0)
AND
False (0)
False (0)

·         For Or operator:

Condition
Operator
(OR)
Condition
Result
True (-1)
OR
True (-1)
True (-1)
True (-1)
OR
False (0)
True (-1)
False (0)
OR
True (-1)
True (-1)
False (0)
OR
False (0)
False (0)

·         For NOT operator:


Condition
Result
True (-1)
False (0)
False (0)
True (-1)

9.      What is String Operator? Explain with examples.
Þ     String operator is a symbol like + (plus), which is used to combine two or more strings. For example: +

10.  Write any ten possible conditions or Boolean expressions that exist between A and B, where A=12 and B=13.
Þ     Any ten possible conditions or Boolean expressions that exist between A and B, where A= 12 and B=13 are as follows:
·         A=B
·         A<>B
·         A<B
·         A>B
·         A<=B
·         A>=B
·         A>B OR B>A
·         A<B OR B<A
·         NOT A<B
·         NOT B<A

11.  Define numeric data and string data. Give examples also.
Þ     Definitions:
·         Numeric data:
 All the positive and negative numbers are known as numeric data. For example:  12, 28, 189, -45, -168, etc.

·         String data:
A text value that consists of alphabets, numbers and other special symbols are known as string data. For example:  “Kathmandu”, “Nepal”, etc.

12.  What is constant? List its type with examples.
Þ     Constants are values, which are remained fixed during the execution of a program.  Its types with examples are as follows:
·         Numeric constant
E.g.: 500, 1200, etc.
·         String constant
E.g.: “Kathmandu”, “My name is Sarika Shrestha”, etc.
  
13.  Define string and numeric constant with examples.
Þ     Definitions:
·         String constant:
A text value that consists of alphabets, digits, symbols and other special characters is known as string constant. For example: “PSY”, “CHABAHIL, 7”, etc.

·         Numeric constant:
All numeric values or data i.e. all the positive, negative and decimal numbers are known as numeric constant. For example: 500, 2.8, -92, etc.

14.  What is variable? List its type with examples.
Þ     An identifier or reference or name for the memory address that holds data and changes its value during the execution of a program which is written with the combination of letters, numbers and special characters with certain rules is known as variable. Its types with examples are as follows:
·         Numeric variable
E.g.: N, N&, N%, N#, etc.
·         String variable
E.g.: “Roll$”, “Kathmandu$”, etc.

15.  Define string and numeric variable with examples.
Þ     Definitions:
·         Numeric variable:
A name or reference, which stores a positive or negative number, is known as numeric variable. For example:  A1, N, B#, etc.

·         String variable: 
A name or reference or memory location, which stores alphanumeric characters, is known as string variable. For example: “Kathmandu”, “Saurav”, etc.


16.  Write the characteristics of variable.
Þ     The characteristics of variables are as follows:
·         Each variable has a name. 
·       Each variable has a type.
·        Each variable has a value that we specify. 

17.  List rules for naming variable.
Þ     The rules for naming a variables are as follows:
·         A variable name must start with an alphabet (A to Z or a to z).  “A10” is a valid variable name.
·         A variable name may have 1 to 40 characters in length.
·         A variable name should not contain a blank space or special characters other than letters, numbers, periods (.) and data type declaration symbols ( %, &, !, # and $).  “A 10” is an invalid variable name because of its space.
·         A variable name must not start with “FN”, because it is a reserved for the user-defined function.”FNnum” is an invalid variable name.
·         Other reserved words or keywords of QBASIC are not allowed to use as a variable name. For example, “LET” is an invalid variable name because “LET” is a reserved word of QBASIC.

18.  What are the types of numeric variable? Explain with example.
Þ     The types of numeric variable are as follows:
·         Integers-
Positive or negative whole numbers are known as integers. The legal range of integer data type is from -32,768 to 32,767. QBASIC stores each integer’s value with two bytes of memory. The “%” symbol is used to indicate integers. For example: NUM%, R1%, etc.

·         Long integers-
A long range of whole numbers is known as long integers. The legal range of long integer data type is from -2,147,483,648 to 2,147,483,647. QBASIC needs four bytes memory to store each long integer number. The “&” symbol is used to indicate long integer. For example: NUM&, P&, etc.

·         Single precision-
Single precision stores the number with accuracy up to 7 digits. Single precision numbers can be written in different ways. The most common way to write the number is number with a decimal point. QBASIC needs four bytes memory to store each single precision data. The “!” symbol is used to indicate single precision data. For example: NUM! , P!, etc.

·         Double precision-
Double precision is a numeric data that supports a long range of values with rational parts. Qbasic needs 8 bytes memory to store each double precision. Double precision stores the number with accuracy up to 15 digits. The “#” symbol is used to indicate double precision data. For example: NUM#, P#, etc.

19.  Define implicit and explicit declaration of variable with example.
Þ     Definitions:
·         Implicit declaration:
Declaration of variable at the place of assigning a value to the variable is called implicit declaration. It can be done by using suffix symbols (%, &,!, #, $). For example: LET N$ =”Nepal”: where $is declares as string variable to store string Nepal.

·         Explicit declaration:

Declaration of variable before you use it or before assigning data to the variable in the program is known as explicit declaration. For example: DIM N%, P$: where N% is declared as an integer and P$ is declared as a string variable explicitly.

20.  Write short notes on Qbasic.

Þ     QBASIC stands for Quick Beginner’s All Purpose Symbolic Instruction Code. It is a high-level language which is simple to learn and use, developed by Microsoft Corporation. It was released with MS-DOS 5.0 operating system. It contains two files: QBASIC>EXE and QBASIC.HLP. Since then, nearly every PC user owns their own copy of QBASIC, making it a widely known language. QBASIC can be used for scientific as well as commercial applications.
Submitted to,
Deepak sir