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: