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