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[HOMEWORK II] March 9, 2010

HOMEWORK-IIModern Programming tools and Techniques

Homework Title / No. : IInd Course Code : CAP 310

Course Instructor : BalRaj Kumar Tutor (if applicable) : BalRaj Kumar

Date of Allotment : Date of submission : 21-Feb-10

Students Roll No: RTb805A17 Section No RTb805

Declaration:

I declare that this assignment is my individual work. I have not copied from any other students work or

from any other source except where due acknowledgment is made explicitly in the text, nor has any part

been written for me by another person.

Students Signature : Joginder singh

Evaluators comments:

_____________________________________________________________________

Marks obtained : ___________ out of ______________________

Part-I

Q:1 Explain the term:a) Widening and Narrowing operand conversion

b) Overflow, Underflow, and Exceptions

Ans (a) Widening and Narrowing operand conversionA specific conversion from type S to type T allows an expression of type S to be treated at

compile time as if it had type T instead. In some cases this will require a corresponding action at

run time to check the validity of the conversion or to translate the run-time value of the

expression into a form appropriate for the new type T. For example:

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A conversion from type int to type long requires run-time sign-extension of a 32-bit

integer value to the 64-bit long representation. No information is lost.

A conversion from type double to type long requires a nontrivial translation from a 64-bit

floating-point value to the 64-bit integer representation. Depending on the actual run-time value,

information may be lost.

In every conversion context, only certain specific conversions are permitted. For convenience of

description, the specific conversions that are possible in the Java programming language are

grouped into several broad categories:

Identity conversions

Widening primitive conversions

Narrowing primitive conversions

Widening reference conversions

Narrowing reference conversions

Widening Primitive Conversion

The following 19 specific conversions on primitive types are called the widening primitive

conversions:

byte to short, int, long, float, or double

short to int, long, float, or double

char to int, long, float, or double

int to long, float, or double

long to float or double

float to double

Widening primitive conversions do not lose information about the overall magnitude of a

numeric value. Indeed, conversions widening from an integral type to another integral type do not

lose any information at all; the numeric value is preserved exactly.

Conversion of an int or a long value to float, or of a long value to double, may result in loss ofprecision-that is, the result may lose some of the least significant bits of the value

A widening conversion of a signed integer value to an integral type T simply sign-extends the

two's-complement representation of the integer value to fill the wider format.

A widening conversion of a char to an integral type T zero-extends the representation of

the char value to fill the wider format.

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Despite the fact that loss of precision may occur, widening conversions among primitive types

never result in a run-time exception

An example of a widening conversion that loses precision:

class Test {

public static void main(String[] args) {

int b = 1234567890;

float approx = b;

System.out.println(b - (int)approx);

}

}

which prints:

-46

thus indicating that information was lost during the conversion from type int to type float because

values of type float are not precise to nine significant digits.

Narrowing Primitive Conversions

The following 22 specific conversions on primitive types are called the narrowing primitive

conversions:

short to byte or char

char to byte or short

int to byte, short, or char

long to byte, short, char, or int

float to byte, short, char, int, or long

double to byte, short, char, int, long, or float

Narrowing conversions may lose information about the overall magnitude of a numeric value and

may also lose precision.

The example:

class Test {

public static void main(String[] args) {

float fmin = Float.NEGATIVE_INFINITY;

float fmax = Float.POSITIVE_INFINITY;

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System.out.println("long: " + (long)fmin +

".." + (long)fmax);

System.out.println("int: " + (int)fmin +

".." + (int)fmax);

System.out.println("short: " + (short)fmin +

".." + (short)fmax);

System.out.println("char: " + (int)(char)fmin +

".." + (int)(char)fmax);

System.out.println("byte: " + (byte)fmin +

".." + (byte)fmax);

}

}

produces the output:

long: -9223372036854775808..9223372036854775807

int: -2147483648..2147483647

short: 0..-1

char: 0..65535

byte: 0..-1

Ans (b) Overflow, Underflow, and Exceptions

Overflow And Underflow

Overflow and underflow is a condition where you cross the limit of prescribed size for a datatype. When overflow or underflow condition is reached, either the program will crash or the

underlying implementation of the programming language will have its own way of handingthings.

In Java arithmetic operators dont report overflow and underflow conditions. They simply

swallow it! It is a very dangerous thing to do. If one doesnt know how Java handles overflow

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and underflow then he will not be aware of things happening behind while doing arithmetic

operations.

Overflow and Underflow in Java int operators

Arithmetic integer operations are performed in 32-bit precision. When the resultant value of anoperation is larger than 32 bits (the maximum size an int variable can hold) then the low 32 bits

only taken into consideration and the high order bits are discarded. When the MSB (most

significant bit) is 1 then the value is treated as negative.

Overflow and Underflow in Java floating point operators

While using java floating point operators, overflow will result in Infinity and underflow will

result 0.0 As a general rule here also Java doesnt throw an error or exception for overflow and

underflow.

Exceptions Exceptions in java are any abnormal, unexpected events or extraordinaryconditions that may occur at runtime. They could be file not found exception, unable to get

connection exception and so on. On such conditions java throws an exception object. JavaExceptions are basically Java objects. No Project can never escape a java error exception.

Java exception handling is used to handle error conditions in a program systematically by taking

the necessary action. Exception handlers can be written to catch a specific exception such as

Number Format exception, or an entire group of exceptions by using a generic exceptionhandlers. Any exceptions not specifically handled within a Java program are caught by the Java

run time environment

An exception is a subclass of the Exception/Error class, both of which are subclasses of the

Throwable class. Java exceptions are raised with the throw keyword and handled within a catchblock.

A Program Showing How the JVM throws an Exception at runtime

public class DivideException

{public static void main(String[] args)

{division(100,4);

division(100,0);System.out.println("Exit main().");

}

public static void division(int totalSum, int totalNumber){

System.out.println("Computing Division.");

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int average = totalSum/totalNumber;

System.out.println("Average : "+ average);

}}

Q:2 Write a code segment that circularly shifts the values of int variable a, b, c and d, for

example if the variable values are initially 10, 20, 30 and 40 respectively, then the final

values are 40, 10, 20 and 30 respectively. It may be convenient to introduce a temporary

variable to accomplish this task.

Answer:

class circularsfts

{

public static void main(String args[])

{

int a[]={10,20,30,40};

int temp,i,c;

temp=0;

c=a[3];

for(i=3;i>0;i--)

{a[i]=temp;

a[i]=a[i-1];

}

a[0]=c;System.out.println("the circular sifted aray is ");

for(i=0;i

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Q:3 How many parameters does a default constructor require? Why?

Answer If we don't define a constructor for a class, a default parameter less constructor is

automatically created by the compiler. The default constructor calls the default parent constructor

(super ()) and initializes all instance variables to default value (zero for numeric types, null for

object references, and false for Booleans ).

If you define any constructor for your class, no default constructor is automatically created. Thus

default constructor requires no parameter.

Part B

Q:4 Write an array definition for an array coefficient that is initialized with the following values

1.4, 4.30, 5.12, 6.9, 6.21, 7.31, 11.4, 11.28 and 11.29.

Answer :

import java.util.*;

class array_float

{


{

float arr1[]={1.4, 4.30, 5.12, 6.9, 6.21, 7.31, 11.4, 11.28 ,11.29};

for(i=0;i

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(b) Sets the value of each element in score so that it matches its subscript value.

(c) Displays the values of the last five elements of scores.

(d) Is the value 3.1415 a legal subscript value for score? Explain.

(e) Is the value 3.1415 a legal element value for score? Explain.

Answer :

Array score with 40 elements

import java.util.*;

class Ele_score

{public static void main(String arg[])

{

Scanner input=new Scanner(System.in);

double score[ ]=new double[40];int n;

System.out.print("array score:");

for(i=0;i

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Q:6 Program to input a set of names into an array and print each name with the no. of characters

in it and print each name by replacing all occurrences of the alphabet a and A with the

symbol *. Use at least two user-defined classes.

Answer :

import java.util.*;

class print _element

{

Void find(char a[ ][ ])

{

int i,j;

for(i=0;i

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System.out.print ("\t"+a[i][j]);

}

}

}

}

class jogin

{


{

finda fa=new find();

Scanner input=new Scanner ();

char name[ ][ ]=new int [10][30];

int ii.jj;

for(ii=0;ii

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