INFORMATICS PRACTICES
CLASS XII
UNIT II
PROGRAMMING (JAVA GUI PROGRAMMING)
Q1 What is RAD?
A1. Rapid Application Development describes a method of
developing software through the use of pre-programmed tools or wizard. The
pre-programmed tools or controls are simply dropped on the screen to visually
design the interface of application.
Q2 What is event driven programming?
A2. This programming style responds to the user events and
is driven by the occurrence of user-events.
Q3 What is object oriented programming?
A3. This programming style emphasizes upon objects; an
object is an identifiable entity with some characteristics and behavior.
Q4. What are event, message, properties and what is the
relationship between them?
A4. Events are activities that take place either due to user
interaction or due to some internal changes. E.g. User clicks upon a command
button or text of a textbox changes owing to a calculation.
A message is the information / request sent to an
application about the occurrence of an event.
Properties are characteristics of an object that controls
its appearance and behavior.
Relationship – properties can be thought of as an object
attributes methods as its actions and events as its responses.
Q5. What are containers? Give e.g.?
A5. Containers are those controls that can hold other
controls inside them e.g. frame (JFrame), panel (JPanel), label (JLabel) e.t.c
are containers.
Q6. Name the character set supported by java.
A6. Unicode
Q7. What are keywords can keywords be used as identifiers?
A7. Keywords are the words that convey special meaning to a
language compiler.
These are reserved for special purposes and must not be used
as normal identifiers names.
Q8. What is an identifier?
A8. Identifiers are fundamental building blocks of a program
and are used as the general terminology for the names given to different parts
of the program viz.variables, objects, classes, functions, arrays e.t.c
Q9 what are literals? How many types of integer literals are
available in java?
A9. Literals (often referred as constants) are data items
that are fixed data values. Java allows several kinds of literals:
- integer-literals
- floating-literals
- Boolean literals
- Character-literals
- String-literal
- The null literal
Q10.How many types of integer’s constants are allowed in
java: how are they written?
A10.Java allows three types of integer laterals:
1)decimal(base10).these are the integer literals that begin
with a non – zero digit.eg,1234.
2)octal (base8)these are the integer literals that begin
with a zero eg,to write octal no. 24 ,you need to write :024.
3)hexadecimal (base
16).these are the integer literal that begin with 0x or 0X eg,to write
hexadecimal no. 2AF9,you need to write:0x2AF9.
Q11.what will be the result of a = 5/3 if a is 1)float 2)int?
A11.1)1.0 2)1
Q12.The expression 8%3 evaluates to___.
A12. 2
Q13.What will be the value of j = -- k + 2*k + l++
If k is 20
and l is 10 initially?
A13. 67, because
j=19+2*19+10
= 19+38+10=67
Q14.Name the eight primitive Java types.
A14. The eight primitive types are:
1)byte 2)char
3)short 4)int
5)long 6)float
7)double 8)Boolean
Q15. Which package is always imported by default?
A15. The java.lang package is always imported by deafault.
Q16. To what value is a variable of a string type
automatically initialized?
A16. The default value of the string type is NULL.
Q17. To what value is a variable of the bollean type
automatically initialized?
A17. The default value of the boolean type is FALSE.
Q18. What is casting? When do we needed?
A18. The casting is a form of conversion which uses the cast
operator to specify the type name in parenthesis and is placed in front of the value to be converted.
Example: Result= (Float) total/count:
They are helpful in situations where we temporarily
need to treat the value as another type.
Q19. What is a literal?
A19. A literal is a sequence of characters used in a program
to represent a constant value.
For example: A is a literal that represents the value A , of type
char and 17L is a literal that represents a number 17 as a value of type long.
A literal is a way of writing a value.
Q20. What is the significance of the break statement in a switch statement?
A20. In a switch statement
after matching case’s code is executed, it stops only when it
encounters
break or closing brace(}) of switch.
So break statement
acts as terminating statement for match case in a switch statement.
Q21. What is the purpose of break statement in a loop?
A21. In a loop the break statement terminates the loop when
it gets executed.
Q22. What is the effect of absence of break in a switch
statement?
A22. If we do not give break after each case then java will
start executing the statement for
matching case and keep on executing statements for following cases as well,
until either a break statement is found or switch statements end is encounter.
Q23. What is the significance of default clause in a switch
statement ?
Or
What is the
purpose of default clause in a switch statement?
A23. The default statement gets executed when no match is
found.
Q24. What is meant by an entry controlled loop? Which java
loops are entry controlled?
A24. Loop which evaluates its test expression at the
beginning of the loop before executing its loop body statements is called entry
controlled loop. While loop is an entry controlled loop.
Q25. How many times will each of the following loop will
execute? Which one of these is an entry controlled loop and which one is an
exit controlled loop?
A25.
|
Loop1:
|
Loop2 :
|
|
int sum 0, i = 5 ;
|
int sum 0 , i 5 ;
|
|
do
|
While ( i<5) ;
|
|
{ sum i ; i ; ) while (1<5);
|
{ sum i; i }
|
A25. Loop 1 will execute once and Loop 2 will execute 0
times.
Loop1 is exit controlled loop and Loop2 is entry controlled
loop.
Q26. Write a for loop that
displays the number from 51 to 60.
A26. int i =0;
for ( i=51;i<=60; i++)
{
system.out.print(i
+” “);
}
Q27. Write a for loop that displays a number from 10 to 1
i.e., 10,9,8……..3,2,1
A27. int i ;
for( i=10;
i>=1 ; i--)
{
system.out.print(i
+ “ “);
}
Q28. How is swing related to GUI programming?
A28. Swing API includes a rich set of graphical components
for building GUIs and
adding
interactivity to Java Applications. So, whenever GUI programming is done
in Java it is
done through swing API of Java.
Q29. Name two containers for each of the following
categories:
i)
top level
ii)
middle level
iii)
component level
A29.i) Top level containers
JFrame,
JDialog
ii) Middle
level containers
JPanel,
JTabbedPane
iii)Component
level containers
JButton,JLabel
Q30. What is an event? What is an event handler?
A30. An event is occurrence of some activity either
initiated by user or internally by
system.
Event handler of Event Listener. It
is implemented in form of code. It receives and handles events, eg, when a
button gets clicked, some value is computed and displayed for user’s reference.
Q31. What is a layout manager?
A31. Layout managers
enable to control the way in which visual components are
arranged in GUI forms by determining the size and position
of components within containers.
Q32. What is the default name of action event handler of a
button namely TestBtn?
A32. TestBtnActionPerformed is the default name of action
event handler of a button “TestBtn”.
Q33. What is a label used for?
A33. A label control (created through JLabel class type
components) displays text and /or image that user can not directly change or
edit.
Q34. What command do you need to write in action performed
() event handler of a button in order to make it exit button.
A34. Syatem.exit(0);
Q35. What methods would you use in order to simulate buttons
(namely OKBtn) click event, without any mouse activity from users side?
A35. OKBtn. Doclick();
Q36. A label by default allows only one line of text to be
displayed . can you displayed multiple
lines of text in a label? If so how ?
A36. Yes, we can display multiple lines of text with in a
label by making use of HTML text. For this we will have to start the text
properties value with <HTML> and then we can use <BR> or <P> tags to force the line breaks.
Q37. You have assigned a foreground color and a background
color through foreground and background properties of a label. But the label is
not showing any backgroubd colour what could be the reason?
A37. The label is filled with background color only if the
property opaque is set to TRUE.The default settings for opaque is false. If the
label is not showing an
Y background color , the reason might be that its opaque
property is set to false.
Q38. What is the difference between text properties of text
field and a text area?
A38. A text fields a text property can hold single line of
text unless it is an HTML text. A text areas text property can hold any number
of line of text depending upon its rows property.
Q39.What is the difference between a text field and a text
area?
A39. A text field allows a user to enter a single line of
text, where as a text area is editing an area for blocks or multiple lines of
text. It allows user to enter multi – lines text. Text area can be constructed
from JTextArea components class and text
field can be constructed from JTextField component class.
Q40. What is the difference between a getText( ) and
getPassword( ) methods?
A40. The getPassword() method of password field returns the
text displayed by the field.
The
getText() method returns the text disaplayed in the text field , label, button
and other components.
Q41. How can you displayed multiple lines of uneditable
text?
A41. Through a text area we can display multiple lines of
text and to make it uneditable we can set its editable property to FALSE.
Q42.Which event get fired when :
i)
User presses enter in a text field.
ii)
User presses enter in a password field
iii)
A check box is clicked
iv)
A radio button has clicked.
v)
A key is typed from keyboard
A42. i) Action
event
ii) Action event
iii)
Item event
iv)
Item Event
v)
Key Typed Event
Q43 If a user presses enter key, while still being with in a
JTextField object what happens?
A43. Action event generated.
Q44. Which controls allow text entry in them?
A44. Controls that allows text entry in them are :
textfield, passwordfield and text area.
Q45. Which property would you set for setting the password
character as “$” ?
A45. To set password character as $ , we will set the
echoChar property of the password field to $.
Q46. Ms Sangeeta has developed the java application through which the
students of her school can view their marks by entering their admission number.
The marks are displayed in various text fields. What should she do so that the
students are able to view but not change
their marks in text field.?
A46. She should make the text field showing marks not
editable
or
She should
deselect the editable property of corresponding text boxes.
Q47. Name the swing API classes that create
i)
A list
ii)
A combo Box
A47. i) List - JList
ii) Combo Box - JComboBox
Q48. Which list property do you set for specifying the
contents of the list?
A48. The model property of the list is used to specify the
contents of the list.
Q49. Which method would you use to determine which index has
been selected in the list?
A49 int getselectedindex ( )
Q50. How would you determine whether 7th item of
a list namely mylist is selected or not?
A50. If method
mylist.isselectedindex(
6) returns TRUE, then the 7th item is selected otherwise not.
Q51. You want to clear the selection in the list namely
chklist. How would you do this?
A51. By using method
chklist.clearselection(
) ;
Q52. What would be the name of the event handler that would
handle the list selection event of a list namely worklist?
A52. worklistvaluechanged()
Q53. How would you ensure that in a list
i)
only a single item get selected
ii)
only a single range of items get selected
iii)
multiple ranges of item get selected
A53. i)
setselectionmode property to SINGLE
ii)
setselectionmode property to SINGLE _INTERVAL
iii)
setselectionmode propertyto MULTIPLE_INTERVAL
Q54. While working in net beans, Rjmeeta included a list box
in the font. Now she wants the list of her friends names to be displayed in it.
Which property of list box control should she used to do this?
A54. Model
Q55. What is a default list model?
A55. List model
Q56. Is a combo box by default editable? If not, then how
would you make it editable.
A56. By default, the text field of a combo box is uneditable , but you can change it to be
editable by setting its editable property to TRUE . Eg. Checked
Q57. How would you obtain selected item from a combo box?
A57. By using method
object
getselecteditem()
Q58. How would you determine whether a combo box is editable
or not?
A58 Method Boolean is editable () , indicates whether the
combo box is text field is editable or not.
Q59. What event does a Jlist fired when user select an item?
What event does a JList use?
A59. A Jlist files list selection event when user makes a
selection. The event listener is used by a Jlist is listselectionlistener
Q60. What would be the name of event handler method in the
list selection listener interface for a
list namely check list to handle its item selection?
A60. Checklistvaluechanged ()
Q61. A list namely my list has selection mode property to
set to single_interval. How would you obtain
i)
the indices of selected value?
ii)
The selected values?
A61. i) By using method
mylist.getselectedindices()
ii) By
using method
mylist.getselectedvalues()
Q62. By default a combo box does not offer editing features.
How would you make a combo box editable?
A62. By setting the editable property of a combo box we can
make it editable.
Q63. What method controls the vertical position of the text
related to an image in a label?
A63. Setverticaltextposition()
Q64. Which swing component provides a pop up list?
A64. jcombobox component
Q65. Which property ensures that the combo box is editable?
A65. Editable property when set to true( i.e. ischecked) ensures
that the combo box is editable.
Q66. How are following passed in java:
i)
primitive type
ii)
reference type
A66 i) by value
ii) by reference
Q67. How is a constructor invoke?
A67. A constructor is invoked automatically when a new
object is being created
In
other words a constructor is automatically
called with a new operator in order
to create a new object.
Q68. Which method of a class is invoked just once for an
object ?when?
A68. The constructor method.
It
is invoked for initializing values of the object at the of its creation.
Q69. Whats wrong with the following constructor definition
for the class playinfo?
public void
playinfo(int sticks)
{
nsticks=
sticks;
}
A69. A constructor can not have a return type not even void.
Q70. What will be the scope of
i)
a public member?
ii)
a protected member?
iii)
a default member?
iv)
a private member?
A70. i) a public specifier donates a variable
or method as being directly assessable
from all other
classes.
ii) a
protected specifier donates a variable or methods as being public to sub
classes of this class but private
to all other classes outside the current package.
iii)
Members with package access are available to all
classes in the same package, but are not
available to any other classes but not even sub classes
iv)
The private access specifier donates a variable or
method as being private to the class and may not be access outside the class .
Accessing will be done by calling one of the public class method.
Q71. Name the package you need to import for performing data
base connectivity.
A71. java.sql
Q72. Which commands creates package in java?
A72. Package in java is created by package command i.e.,
package name, on top of the source file.
Q73. Define inheritance. What is the inheritance mechanism
in java?
A73. Inheritance is the capability of one class to derive
properties from another class.
Inheritance
in java is implemented by enabling a class to derive properties from another
class by using keyword “extends” at the time of class definition.
Q74. Name various forms of inheritance.
A74. i) Single Inheritance
ii) Multiple Inheritance
iii)
Multilevel Inheritance
iv)
Hierarchical Inheritance
v)
Hybrid Inheritance
Q75. What type of inheritance does java have?
A75. Java supports only these inheritance types:
i) Single Inheritance
ii) Multiple Inheritance
iii) Hybrid Inheritance
Q76. How do you
prevent a sub class from having access to a member of super class?
A76. To prevent a sub
class from having access to a super class member, declare that member as
private.
Q77. What is an abstract class?
A77. An abstract class is the one that simply represents a
concept and whose objects can not be created.
Q78. How do you prevent a method from being overridden? How
do you prevent a class from being inherited?
A78. To prevent a method from being overridden, declare it
is final. To prevent a class from being inherited, declare it as final.
Q79. Assume a class Derv derived from a base class Base.
Both classes contain a member function func( ) that takes no arguments.Write
the definition for a member function of Derv that calls both the func()s.
A79.void call ( )
{ func( ) ;
//
call to member function of derv super.func( );
//
it will call Base’s member function
}
Q80. What is dialog?
A80. A dialog is a small separate window that appears to
either provide or request information to/ from the user.
Q81. What all classes can you use to create dialogs in Java?
Name them.
A81. I) JDialog. Main dialg class ( general purpose dialog)
Q82. Rewrite the following statement using Switch:
if(ch==’E’)
eastern++;
if(ch==’W’)
western++;
if(ch==’N’)
northern++;
if(ch==’S’)
southern++;
else
unknown++;
A82. switch(ch){
case
‘E’ : eastern++;
Break;
case
‘W’ : western++;
Break;
case ‘N’ :
northern++;
Break;
case ‘S’ :
southern++;
Break;
default:
unknown++;
}
Q83. How many times are the following loops executed?
a)
x=5 ; y=50; b) int m=10,n=7;
while(x<=y) { while(m%n>=0)
{
x=y/x; m=m+1;
} n=n+2;
}
A83. a) Infinite number of times since y/x will always be
less than y.
b) Infinite
number of times since mod operation always gives a number >=0.
Q84. Given the following code fragment:
i= 2;
do {
system.out.println(i);
i
+=2;
}
while(i
< 51);
JOptionPane.showMessageDialog(null,
“Thank You”);
Rewrite the
above code using while loop.
A84. i=2;
while(i<51)
{
system.out.println(i);
i+2=2;
}
JOptionPane.showMessageDialog(null,
“Thank You”);
Q85. Given the following code fragment:
i= 100;
while(i>0)
system.out.println(i--);
JOptionPane.showMessageDialog(null,
“Thank You”);
Rewrite the
above code using do.while loop.
A85. i=100;
do {
system.out.println(i--);
} while(i>0);
JOptionPane.showMessageDialog(null,
“Thank You”);
Q86. Rewrite the following while loop into a for loop:
int
stripes=0;
while
(stripes<=13)
{
if(stripes
% 2 ==2)
{ system.out.println(“Colors code RED”);
}
else
{
system.out.println(“Colors
code BLUE”);
}
system.out.println(“NEW STRIPE”);
stripes=stripes
+ 1;
}
A86. for (int stripes
=0;stripes <=13;stripes++)
{
if(stripes
% 2 ==2)
{
system.out.println(“Colors
code RED”);
}
else
{ system.out.println(“Colors code
BLUE”);
}
system.out.println(“NEW
STRIPE”);
}
Q87. In the code fragment given below, what happens when
choice equals 5?
num= 0 ,
num2 =0;
if(choice
==1) {
num=11;
num2=110;
}
Else if
(choice==2){
num=20;
num2=220;
}
JOptionPane.showmessageDialog(null,”num=”+num+”,num2=”
+num2);
A87 The message dialog box will show the value as :
Num=0 ,
num2= 0
Q88. What value is assigned to num in the following code fragment when choice is
equal to 2?
switch(choice){
case1 : num
=1;
break;
case2 : num =2;
case3 : num
=3;
break;
default: num =0;
}
A88 Value is 3
Q89. What will be the value produced by following code
fragment:
float x=9;
float y=5;
int z=
(int) (x/y);
switch(z) {
case
1 : x = x+2;
case 2 : x = x+3;
case
3 : x = x+1;
}
system.out.println(“value
of x= “ + x);
A 89. value of x =15
Q90. What is explicit and implicit type conversion?
A90. An implicit type conversion is performed by the
compiler without programmer’s intervention. It is applied generally whenever
differing data types are intermixed in an expression, so as not to lose
information.
An explicit
conversion is a user defined that forces an expression to be of specific type.
For eg. , to make sure that the expression (x +y )/2 evaluates to type float,
write it as: (float) (x+y) /2
Q91. What is type casting and type cast operator?
A91. The explicit conversion of an operand of a specific
type is called type casting.
Syntax : (type) expression
Where type
is a valid java data type and is called type cast operator.
For eg.
float
x=3.1;
int
i = (int) x;
Q92. Write the output of the following code fragments:
a)
int i , j , n ;
n=0,i=1;
do
{ n++;
i++;
} while (i<=5;
Output : No Output
b)
int i=1 , j=0 ,
n=0 ;
while (i<4)
{ for(j=1;j<=i;j++)
{ n+=1;
}i
=i +1;
}system.out.println(n);
Output : 6
c)
int j=1 ,s=0 ;
while (j<10)
{ system.out.println(j
+ “ + “);
s=s+j;
j=
j + j %3;
}
system.out.println(“=” +s);
Output : 1 + 2+4 +5 +7 + 8 + = 27
d)
int i=3 , n=0 ;
while (i<4)
{n++ , i-- ;
}system.out.println(n);
Output : infinite loop ; no output
Q93. Find out the errors in the following, if any :
a)
m=1;
n=0;
for(; m+n <19 ; ++n)
system.out.println(“hello\n”);
m=m+10;
Output: No Error
b)
while (ctr != 10); {
ctr= 1;
sum
= sum +a;
ctr=
ctr +1;
}
Output : No syntactical error as such. But the test expression of while
loop is followed by semicolon (;). Hence it is an empty loop.
c)
for (
a=1,a>10;a=a+1)
{ ………………
}
Output : Initialization and test expression are separated by comma(,) .
This should be replaced by a semicolon (;) i.e. as :
for
( a=1;a>10;a=a+1)
{ ………………
}
Q94. Identify
the errors in the following code that is written in action event handler of a
button
namely OKBtn.
double d = nameTF.getText();
string
age = ageTF.getText();
double marks = Double.parseDouble
(marksTF.getText());
A94. In a line 1 name TF.getText () will
return a string, which has been assigned to double
d.
String obtained has to be parsed to double before assignment.
Thus the first code should be:
double
d = Doublr.parseDouble(nameTF.getText());
Q95. What are
these methods used for :
i)
isEditable() à it returns the
setting(true/false) whether the user can edit the text in the text area.
ii)
setEditable () à Sets whether the user
can edit the text in the text area.
iii)
getEchoChar() à It returns the echo
character i.e. the character that will replace the text entered in the password
field.
Q96. What are
events? What major events are associated with the following :
i)
Text Field à
Action event
ii)
Password Field à
Action Event
iii)
Check Box à
Item Event
iv)
Radio Button à Item Event
A96. An event is
an object that gets generated when user does something such as mouse
click,
dragging, pressing a key on the keyboard etc.
Q97. Write code
of item event handler of a check box( namely incCB) that increments a
variable
total and displays in a label (namely count) if the check box is selected.
A97.
incCBItemStateChanged method
if
(incCB.isSelected())
{
total=total +1 ;
count.setText(
“ “ + total);
}
Q98.Write code
for the event handler of a radio button so that when it is selected/
unselected,
its text
changes to “ I am selected “ or “I am unselected “.
A98.
RDItemStateChanged Method
if
(RD.isSelected())
RD.setText(“
I am selected”);
Else
RD.setText(“
I am unselected”);
Q99. Compare and
contrast a list box and a combo box.
A99. A list is
graphical control that displays a list of items in a box where from the
user can make selections.It is different from combo box in many ways:
i)
A list box doesn’t have a text field to do editing,
whereas the combo box have.
ii)
In a list the user must select the items directly from
the list , whereas in a combo box user can do editing if requires.
Q100 Define a
method and its prototype.
A100. A method/
function is a sequence of statements that carry out specific task(s). The first
line of
method definition is the prototype of the method.
Example:
int
absval( int a)
and
static int maximum ( int a , int b)
Q101. What are
actual and formal parameters of a method?
A101. The
parameters that appear in method definition are called formal parameters and
the
parameters
that appear in the method call statement are called actual parameters.
For example:
int
mult( int x, int y)
{
return
x * y ;
}
void
test {
int
length =10;
int
width =5;
int
area= mult (length, width); }
In above example x,y are formal
parameters and length, width are actual parameters.
Q102.Write the
difference between call by value and call by reference.
A102. In call
by value, the called method creates its own work copy for the passed
parameters
and copies the passed values in it.Any changes that take place remain in
the
work copy and the original data remains intact.
In
the call by reference, the called method receives the reference to the passed
parameters and through this reference, it
accesses the original data. Any changes that
take place are reflected in the original
data.
Q103. What is
constructor and how it get invoked?
A103. Job of
initializing an object with some legal values is carried out by the constructor
of
the class the object belongs to. It is automatically invoked every time when an
object
is created.
For example:
Sample
obj1= new Sample();
Q104. How are parameterized constructors
different from non-parameterized
constructors?
A104. A
constructor taking no arguments is a non parameterized default constructor.
A constructor receiving arguments is known
as parameterized constructor.
With non- parameterized constructor,
objects are created just the same way as
variables of other data types are
created.
For example:
X
O1 =new X(); // NON-
PARAMETERIZED CONSTRUCTOR
Y
O1= new Y (5); // PARAMETERIZED CONSTRUCTOR
Q105. How
are private members different from public members of the class?
A105. Private
members are private to the class and cannot be accessed outside the class.
But it can be called by the public
members of the class.
Where as public members can be accessed
directly by all other classes. They
are used to access the private
members of the class.
Q106. How protected members are are
different from private and public members of the
class?
A106. Protected members can be
directly accessed by all the classes in the same
package, as that of the class I
which the member is and sub classes of other
package. Whereas private members
cannot be accessed outside the class, even in
sub classes of the class and public
members can be directly accessed by all other
classes.
Q107.How does class enforce information
hiding?
A107. Class enforces information
hiding by using various access specifiers. Access
specifiers control access to members
of a class from within a java program. The
access levels supported by java are : private,
public, protected and default.
Depending upon the access level of a
member of a class, access to it is denied or
allowed.
Q108. What is package? How do we
tell java that we want to use a particular package in
a file?
A108. When a largish program is to
be written, it is often advantageous to divide the
program up into chunks(modules) and
compile the parts separately. This option is
particularly desirable when several
programmers are jointly developing a large
program. Such modules of code are
called packages in java.
To use all the classes and interfaces
from a package, for instance, the entire
graphics package, use the import
statement with the * wild card character.
Q109. How do we design a package?
A109. Package can be created by
using the package statement as shown in following
example:
Package
graphics; //graphics is a name of
package
class circle {
……… // circle and rectangle
are members of graphics package
}
class rectangle {
…….. }
Q110. How the visibility mode does
controls the access of members in the derived class?
Explain with examples.
A110. Visibility modes are:
i)
Private :
These are accessible only inside the class
ii)
Public :
These are accessible in all the classes
iii)
Protected: These
are accessible in any class in the same package.
iv)
Default : These
are declared without any access specifiers. These are accessible only inside
classes that are in same package.
v)
Private Protected
: These are accessible only from sub classes (whether in same package or any
other package)
Q111. A class One with data members
int a and char b inherits from another class Two
with data members float f and
int x. Write definitions for One and Two for the following situations:
i)
Objects of both the classes are able to access all data
members of both the classes.
ii)
Only the members of class one can access all the data
members of both the classes.
A 111. i) public class Two
{
public
float f ;
public
int x;
}
public class One extends Two
{
public
int a ;
public
char b;
}
ii) public class
Two
{
protected
float f ;
protected
int x;
}
public class One extends Two
{
private int a ;
private
char b;
}
Q112.Write code fragment to obtain a
number from user and display whether it is odd or
even. Make use of dialogs only.
A112. int num=0;
num=
Integer.parseInt(JOptionPane.showInputDialog(“Enter the number:”));
if
(num % 2==0)
JOptionPane.showInputDialog(null,”
Entered number is even”);
else
JOptionPane.showInputDialog(null,“Entered
number is odd“);
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