II B.Tech II Sem CSE Java Lab Exercise - 2 d(Operations, Expressions, Control-flow, Strings)

d) Implementing StringBuffer

Aim: To write a JAVA program using StringBuffer to delete, remove character

Description:





Program:

class stringbufferdemo 
{
public static void main(String[] args) 
{
StringBuffer sb1 = new StringBuffer("Hello Gandi");
sb1.delete(0,6);
System.out.println(sb1);
StringBuffer sb2 = new StringBuffer("Some Content"); 
System.out.println(sb2);
sb2.delete(0, sb2.length()); 
System.out.println(sb2);
StringBuffer sb3 = new StringBuffer("Hello Netaji"); 
sb3.deleteCharAt(0);
System.out.println(sb3);
}
}

Output:


netaji gandi Sunday, December 29, 2019
II B.Tech II Sem CSE Java Lab Exercise - 2 c(Operations, Expressions, Control-flow, Strings)

c) Merge sort:

Aim: To write a JAVA program to sort for an element in a given list of elements using merge sort

Description:


Program:


import java.util.*; 
class mergedemo 
{
public static void main(String args[]) 
{
int n1,n2,i,j,k;
int a[ ]=new int[20];
int b[ ]=new int[20];
int c[ ]=new int[20];
Scanner s = new Scanner(System.in);
System.out.println("Enter number of elements in first array:");
n1 = s.nextInt();
System.out.println("Enter sorted elements of first array:");
for (i = 0; i < n1; i++)
a[i] = s.nextInt();
System.out.println("Enter number of elements in second array:"); 
n2 = s.nextInt();
System.out.println("Enter sorted elements of second array:");
for (j = 0; j < n2; j++)
b[j] = s.nextInt();
i = 0;
j = 0;
k = 0;
while((i < n1) && (j <n2))
{
if(a[i] > b[j]) 
c[k++] = b[j++]; 
else
c[k++] = a[i++];
}
while(i < n1)
c[k++] = a[i++];
while(j < n2)
c[k++] = b[j++];
System.out.println("After merging the elements are:\n"); 
for(i = 0; i < (n1 + n2); i++)
System.out.print("\t"+c[i]);
}
}

Output:


netaji gandi
II B.Tech II Sem CSE Java Lab Exercise - 2 b(Operations, Expressions, Control-flow, Strings)

b) Bubble sort

Aim: To write a JAVA program to sort for an element in a given list of elements using bubble sort

Description:


Program:

import java.util.Scanner; 
class bubbledemo
{
public static void main(String args[]) 
{
int n, i,j, temp;
int a[ ]=new int[20];
Scanner s = new Scanner(System.in); 
System.out.println("Enter total number of elements:"); 
n = s.nextInt();
System.out.println("Enter elements:");
for (i = 0; i < n; i++)
a[i] = s.nextInt();
for(i=0;i<n;i++)
{
for(j=0;j<n-1;j++) 
{
if(a[j]>a[j+1]) 
{
temp=a[j]; 
                                        a[j]=a[j+1]; 
                                        a[j+1]=temp;

}
}
System.out.println("The sorted elements are:"); 
for(i=0;i<n;i++)
System.out.print("\t"+a[i]);
}
}

Output:



netaji gandi
II B.Tech II Sem CSE Java Lab Exercise - 2 a(Operations, Expressions, Control-flow, Strings)

a) Implementation of Binary search mechanism

Aim: To write a JAVA program to search for an element in a given list of elements using binary search mechanism

Description:


Program:

import java.util.Scanner; 
class binarysearchdemo 
{
public static void main(String args[]) 
{
int n, i, num,first, last, middle;
int a[ ]=new int[20];
Scanner s = new Scanner(System.in); 
System.out.println("Enter total number of elements:"); 
n = s.nextInt();
System.out.println("Enter elements in sorted order:"); 
for (i = 0; i < n; i++)
a[i] = s.nextInt();
System.out.println("Enter the search value:");
num = s.nextInt();
first = 0;
last = n - 1;
middle = (first + last)/2; 
while( first <= last )
{
if ( a[middle] < num )
first = middle + 1;
else if ( a[middle] == num ) 
{
System.out.println("number found");
break; 
}
else 
{
last = middle - 1; 
}
middle = (first + last)/2; 
}
if ( first > last )
System.out.println( " Number is not found"); 
}
}

Output:






netaji gandi
II B.Tech II Sem CSE Java Lab Exercise - 1 d(Basics)

d) A case study

Aim: A case study on public static void main(250 words)

Case study:




 The program structure of a simple java program is given below with different steps

Step-1: 
         Click start+run and then type notepad in run dialog box    and click OK. It displays Notepad. 


Step-2: 
      In run dialogbox type cmd and click OK. It displays command prompt.

Step-3
         Type the following program in the Notepad and save the program as “example.java” in a current working directory. 


             class example

             {

                 public static void main(String args[]) 
                 {
                     System.out.println(“Welcome”); 
                 }

             }


Step-4 (Compilation): To compile the program type the following in current working directory and

then click enter.

c:\xxxx >javac example.java

Step-5 (Execution): To run the program type the following in current working directory and then


click enter.

c:\xxxx>java example

Explanation:
 Generally the file name and class name should be same. If it is not same then the java file can be compiled but it cannot be executed. That is when execution it gives the following error
Exception in thread "main" java.lang.NoClassDefFoundError: ex 
 In “public static void main(String args[])” statement
  •   public is an access specifier. If a class is visible to all classes then public is used
  •   main() must be declared as public since it must be called by outside of its class.
  •   The keyword static allows main() to be called without creating object of the class.
  •   The keyword void represents that main( ) does not return a value.
  •   The main method contains one parameter String args[].
  •   We can send some input values (arguments) at run time to the String args[] of the main
    method . These arguments are called command line arguments. These command line
    arguments are passed at the command prompt. 
     In System.out.println("Welcome"); statement
  •   System is a predefined class that provides access to the system.
  •   ouis the output stream.
  •   println() method display the output in different lines. If we use print() method it display the
    output in the same line

netaji gandi
II B.Tech II Sem CSE Java Lab Exercise - 1 c(Basics)

c) Bike Race

Aim: Five Bikers Compete in a race such that they drive at a constant speed which may or may not be the same as the other. To qualify the race, the speed of a racer must be more than the average speed of all 5 racers. Take as input the speed of each racer and print back the speed of qualifying racers.

Description:


Program:

import java.util.*; 
class racedemo 
{
public static void main(String[] args) 
{
float s1,s2,s3,s4,s5,average;
Scanner s = new Scanner(System.in); 
System.out.println("Enter speed of first racer:");
s1 = s.nextFloat();
System.out.println("Enter speed of second racer:"); 
                s2 = s.nextFloat();
System.out.println("Enter speed of third racer:");
s3 = s.nextFloat();
System.out.println("Enter speed of fourth racer:"); 
                s4 = s.nextFloat();
System.out.println("Enter speed of fifth racer:");
s5 = s.nextFloat();
average=(s1+s2+s3+s4+s5)/5;
if(s1>average)
System.out.println("First racer is qualify racer:"); 
else if(s2>average)
System.out.println("Second racer is qualify racer:"); 
else if(s3>average)
System.out.println("Third racer is qualify racer:"); 
else if(s4>average)
System.out.println("Fourth racer is qualify racer:"); 
else if(s5>average)
System.out.println("Fifth racer is qualify racer:");

}


Output:





netaji gandi
II B.Tech II Sem CSE Java Lab Exercise - 1 b(Basics)

b) Roots of a quadratic equation

Aim: To write a java program that display the roots of a quadratic equation ax2+bx=0. Calculate the discriminate D and basing on value of D, describe the nature of root.

Description:



Program:


import java.util.*; 
class quadraticdemo 
{
public static void main(String[] args) 
{
int a, b, c;
double r1, r2, D;
Scanner s = new Scanner(System.in); 
System.out.println("Given quadratic equation:ax^2 + bx + c"); 
                System.out.print("Enter a:");
a = s.nextInt();
System.out.print("Enter b:");
b = s.nextInt();
System.out.print("Enter c:");
c = s.nextInt();
D = b * b - 4 * a * c;
if(D > 0)
{
System.out.println("Roots are real and unequal"); 
                        r1 = ( - b + Math.sqrt(D))/(2*a);
r2 = (-b - Math.sqrt(D))/(2*a); 
System.out.println("First root is:"+r1); 
System.out.println("Second root is:"+r2);
}
else if(D == 0) 
{
System.out.println("Roots are real and equal"); 
                        r1 = (-b+Math.sqrt(D))/(2*a); 
                        System.out.println("Root:"+r1);

else 
{
System.out.println("Roots are imaginary"); 
}
}
}

Output:


netaji gandi
II B.Tech II Sem CSE Java Lab Exercise - 1a (Basics)

a) Displaying default value of all primitive data types

Aim: To write a JAVA program to display default value of all primitive data type of JAVA

Description:




Program:


class defaultdemo 
{
         static byte b;
         static short s;
         static int I;
         static long l;
         static float f;
         static double d;
         static char c;
         static boolean bl;
         public static void main(String[] args) 

        {
               System.out.println("The default values of primitive data types are:");   
               System.out.println("Byte :"+b);
               System.out.println("Short :"+s);
               System.out.println("Int :"+i);

               System.out.println("Long :"+l); 
               System.out.println("Float :"+f);          
               System.out.println("Double :"+d); 
               System.out.println("Char :"+c); 
               System.out.println("Boolean :"+bl);
        } 
}


Output:



netaji gandi
IT JNTUK R19 SYLLABUS (1-1 and 1-2)

DEPARTMENT OF INFORMATION TECHNOLOGY      COURSE STRUCTURE AND SYLLABUS 

For 

B. Tech INFORMATION TECHNOLOGY 

(Applicable for batches admitted from 2019-2020)





netaji gandi Thursday, December 26, 2019

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