Data Types of C#.Net Interview Questions(26)
1.How
Data types can be Categorized in C#.Net?
A)
Data types can be Categorized into two types they are
Ø Value Types
Ø Reference Types
2.What
are the broad classifications of data
types available in C#?
A)Data
types can be broadly divided into 2 types.They are:
1. Built in data
types.
2. User defined
data types.
3.List
Some of the Built in datatypes in C#?
A)Smoe of
exteremed built in datatypes in c# are:
Ø Int
Ø Float
Ø String
4.List the Different types in c#.Net?
A)
DataType
|
Common
Language Runtime Structure
|
StorageAllocation
|
Value
Range
|
||
Boolean
|
System.Boolean
|
2 bytes
|
True or False.
|
||
Byte
|
System.Byte
|
1 byte
|
0
through 255 (unsigned).
|
||
Char
|
System.Char
|
2 bytes
|
|
||
Date
|
System.DateTime
|
8 bytes
|
|
||
Decimal
|
System.Decimal
|
16 bytes
|
|
||
Double
(double-precision
floating-point)
|
System.Double
|
8 bytes
|
-1.79769313486231570E+308
through
-4.94065645841246544E-324
for negative values; 4.94065645841246544E-324 through
1.79769313486231570E+308 for positive values.
|
||
Integer
|
System.Int32
|
4 bytes
|
|
||
Long
(long
integer)
|
System.Int64
|
8 bytes
|
-9,223,372,036,854,775,808
through 9,223,372,036,854,775,807.
|
||
Object
|
System.Object (class)
|
4 bytes
|
Any type
can be stored in a variable of type Object.
|
||
Short
|
System.Int16
|
2 bytes
|
|
||
|
System.Single
|
4 bytes
|
|
||
String
(variable-length)
|
System.String (class)
|
Depends
on implementing platform
|
|
User-Defined Type
(structure)
|
|
Depends on implementing platform
|
|
In this Data Types can
be categroized in C#.Net.
For More Info Visit:
5.What are the default
values for bool,int,double,string,char,reference-type variables?
A)When the types are
declared then they have default values during declaration.It can be listed in
below tabular format.
Type
|
Default Value
|
bool
|
False
|
int
|
0
|
double
|
0
|
string
|
“”
|
char
|
‘’
|
Reference type
|
Null
|
6.If you declare a
variable without any value assignment
either of bool,int,double,string,char?
A)It gives an error
because bool,int,double,string,char types are value types.All value types
requires values.
7. How to declare a constant variable in C#? What is
the use of the const keyword?
A)If a variable needs to
have a fixed value, that may not be changed across the application's
life, then it may be
declared with the const keyword. The
value assigned to a constant variable (using the const keyword) must be known
at the time of compilation.
8.Can we assign a “null”
to value types?
A)Yes if we make value
types as a nullable types.
E.G:int ?a=null
//Is valid(It is nullable type declaration)
int
a=null //Is not valid
9.What is Nullable types?
A) Nullable types are instances of the Nullable
struct. A nullable type can represent the correct range of values for its
underlying value type, plus an additional null value. For example, a Nullable,
pronounced "Nullable of Int32," can be assigned any value from
-2147483648 to 2147483647, or it can be assigned the null value. A Nullable can
be assigned the values true false, or null.
10.What is Const?
A)Const values won’t be
changed.It can be declared as compile time.use “const” keyword to declare a
variable as constant.
E.G: const int a=2;
11.What is Readonly?
A)These values will be
evaluated at runtime.Even we can declare at compile time and it changes according to runtime declaration.Use
“Readonly” keyword to declares a variable as readonly.
E.G:readonly int b;
12.What is the
difference between const and read only?
A)
Const
|
Read-only
|
Const can only be
initialized at the time of declaration of the field.
|
The value will be
initialized either declaration time or the constructor of the class allowing
you to pass the value at run time.
|
Const values will evaluate
at compile time only.
|
Read only values will
evaluate at runtime only.
|
Const value can’t be
changed these will be same at all the time.
|
Read-only value can be
changed at runtime.
|
13.How do you create user defined data types in C#?
A)You use the struct,
class, interface, and enum constructs to create your own custom types. The .NET
Framework class library itself is a collection of custom types provided by
Microsoft that you can use in your own applications.
14.What is keywords in
C#.Net?
A)Keywords are
predefined reserved identifiers that have special meaning to the
compiler.Keywords cannot be used as variables in your program unless they
include @ as a prefix.
15.How many types of
keywords are there in C#.Net.List them?
A)C#.Net Supports 2
types of keywords.They are:
Ø Reserved Keywords
Ø Contextual Keywords
There are 77 Reserved keywords and 6
contextual keywords present in C#.Net.
16.What is the case used
for keywords in C#.Net?
A)Lower case is used to
represent the keywords in C#.Net.
17.List some of Reserved
Keywords in C#.Net?
A)abstract,event,new,struct,as,explicit,null,switch,base,extern
etc……………..
18.List Contextual
Keywords?
A)There are 6 contextual
keywords are there.They are:
1. Get
2. Partial
3. Set
4. Value
5. Where
6. Yield
Contextual keyword is
used to provide a specific maning in the code,but it is not a reserved word in
C#.Net
19.Define “Get”?
A)”Get” defines an
acessor method or a property or an indexer.
20.Define “Set”?
A) ”Set” defines an
acessor method or a property or an indexer.
21.Define Partial ?
A)It defines an
classes,structs and interfaces throughout the same compilation unit
22.Define Where?
A)It adds constraints
i.e conditions to a generic declaration.
23.Define Yield?
A)It is used an iterator
block to return a value to the enumerator object or to signal the end of
iteration.
24.Define value?
A)Used to set accessors
and to add or remove event handlers.
25.What is a line
terminator in C#.Net?
A)Semicolon(;) is a line
terminator in C#.Net.
26.What are the Program
Control Structures in C#.Net?
A)In C#.Net Program
Control Structures can be classified into following types.They are:
Ø Conditional Statements(Simple If,If Else,Nested
If)
Ø Iteration or Looping type of
statements(For,Ehile,Do While,Foreach)
Ø Other types(Break,continue,jump,etc..)
