R19 JAVA PROGRAMMING LAB

 R19 JAVA PROGRAMMING LAB

Exercise - 1 (Basics)

a) Write a JAVA program to display default value of all primitive data type of JAVA

Program:

class DefaultValues
{
byte b;
short s;
int i;
long l;
float f;
double d;
char c;
boolean bl;
String s;
public static void main(String[] args)
{
DefaultValues df=new DefaultValues();
System.out.println("Byte :"+df.b);
System.out.println("Short :"+df.s);
System.out.println("Int :"+df.i);
System.out.println("Long :"+df.l);
System.out.println("Float :"+df.f);
System.out.println("Double :"+df.d);
System.out.println("Char :"+df.c);
System.out.println("Boolean :"+df.bl);
System.out.println("String :"+df.s);
}
}

Output:


b) Write a java program that display the roots of a quadratic equation ax2+bx+c=0. Calculate the discriminate D and basing on value of D, describe the nature of root.



NOTE:
The java.lang.Math class contains methods for performing basic numeric operations such as the elementary exponential, logarithm, square root, and trigonometric functions.

Program:

//Java Program to Find Roots of a Quadratic Equation
import java.util.Scanner;
class Quadratic
{
public static void main(String[] args)
{
//double a = 2.3, b = 4, c = 5.6;
double a,b,c;
System.out.println("Enter a,b,c values:");
Scanner scan=new Scanner(System.in);
a=scan.nextFloat();
b=scan.nextFloat();
c=scan.nextFloat();
double root1, root2;
double determinant = b * b - 4 * a * c;
// condition for real and different roots
if(determinant > 0)
{
root1 = (-b + Math.sqrt(determinant)) / (2 * a);
root2 = (-b - Math.sqrt(determinant)) / (2 * a);
System.out.format("root1 = %.2f and root2 = %.2f", root1 , root2);
System.out.println("\nRoots are real and different");
}
// Condition for real and equal roots
else if(determinant == 0)
{
root1 = root2 = -b / (2 * a);
System.out.format("root1 = root2 = %.2f;", root1);
System.out.println("\nRoots are real and equal");
}
// If roots are not real
else
{
double realPart = -b / (2 *a);
double imaginaryPart = Math.sqrt(-determinant) / (2 * a);
System.out.format("root1 = %.2f+%.2fi and root2 = %.2f-%.2fi",realPart, imaginaryPart, realPart, imaginaryPart);
System.out.println("\nRoots are imaginary"); //complex and different
}
}
}

Output:


c) 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.

Program:

import java.util.*;
  class Race
  {
            public static void main(String a[]) 
            {
                     int r1,r2,r3,r4,r5,avg;
                     Scanner s=new Scanner(System.in);
                     System.out.println("enter the speed of the r1 r2 r3 r4 and r5");
                     r1=s.nextInt();
                     r2=s.nextInt();
                     r3=s.nextInt();
                     r4=s.nextInt();
                     r5=s.nextInt();
                     avg=(r1+r2+r3+r4+r5)/5;
                     if(r1>avg)
                     {
                               System.out.println("first racer is qualified with a race speed "+r1+"\n");
                     }
                     else if(r2>avg)
                     {
                               System.out.println("second racer is qalified with a race speed "+r2);
                     }
                     else if(r3>avg)
                     {
                               System.out.println("third racer is qalified with a race speed "+r3);
                     }
                     else if(r4>avg)
                     {
                               System.out.println("fourth racer is qalified with a race speed "+r4);
                     }
                     else if(r5>avg)
                     {
                               System.out.println("fifth racer is qalified with a race speed "+r5);
                     }
                     else
                     {
                               System.out.println("no biker is qualified");
                     }
            }
  }

Output:





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