import java.util.Date;publicclassbook{publicstaticvoidmain(String[] args){long second =10000;for(int i=0;i<8;i++){
Date curr =newDate(second);
System.out.println(curr.toString());
second*=10;}}}
9.4
import java.util.Random;publicclassbook{publicstaticvoidmain(String[] args){
Random r =newRandom(1000);for(int i=0;i<50;i++)
System.out.print(r.nextInt(100)+" ");}}
9.5
import java.util.GregorianCalendar;publicclassbook{publicstaticvoidmain(String[] args){
GregorianCalendar g =newGregorianCalendar();
System.out.println(g.get(GregorianCalendar.YEAR)+"/"+g.get(GregorianCalendar.MONTH)+"/"+g.get(GregorianCalendar.DAY_OF_MONTH));
g.setTimeInMillis(123456789876L);
System.out.println(g.get(GregorianCalendar.YEAR)+"/"+g.get(GregorianCalendar.MONTH)+"/"+g.get(GregorianCalendar.DAY_OF_MONTH));}}
import java.util.Scanner;publicclassbook{publicstaticvoidmain(String[] args){
Scanner input =newScanner(System.in);
System.out.print("Enter a b c: ");double a = input.nextDouble();double b = input.nextDouble();double c = input.nextDouble();
QuadraticEquation ass =newQuadraticEquation(a,b,c);if(ass.getDiscriminant()<0)
System.out.println("The equation has no roots.");elseif(ass.getDiscriminant()==0)
System.out.println("One root "+ass.getRoot1());else
System.out.println("Two roots "+ass.getRoot1()+" "+ass.getRoot2());}}classQuadraticEquation{privatedouble a;privatedouble b;privatedouble c;publicQuadraticEquation(double aa,double bb,double cc){
a=aa;
b=bb;
c=cc;}publicdoublegetA(){return a;}publicdoublegetB(){return b;}publicdoublegetC(){return c;}publicdoublegetDiscriminant(){return b*b-4*a*c;}publicdoublegetRoot1(){return(-1*b+Math.sqrt(b*b-4*a*c))/(2*a);}publicdoublegetRoot2(){return(-1*b-Math.sqrt(b*b-4*a*c))/(2*a);}}
9.11
import java.util.Scanner;publicclassbook{publicstaticvoidmain(String[] args){
System.out.print("Enter a b c d e f: ");
Scanner input =newScanner(System.in);double a = input.nextDouble();double b = input.nextDouble();double c = input.nextDouble();double d = input.nextDouble();double e = input.nextDouble();double f = input.nextDouble();
LinearEquation ass =newLinearEquation(a,b,c,d,e,f);if(ass.isSolvable())
System.out.println(ass.getX()+" "+ass.getY());else
System.out.println("The equation has no solutions.");}}classLinearEquation{privatedouble a,b,c,d,e,f;publicLinearEquation(double aa,double bb,double cc,double dd,double ee,double ff){
a=aa;
b=bb;
c=cc;
d=dd;
e=ee;
f=ff;}publicdoublegetA(){return a;}publicdoublegetB(){return b;}publicdoublegetC(){return c;}publicdoublegetD(){return d;}publicdoublegetE(){return e;}publicdoublegetF(){return f;}publicbooleanisSolvable(){return a*d-b*c!=0;}publicdoublegetX(){return(e*d-b*f)/(a*d-b*c);}publicdoublegetY(){return(a*f-e*c)/(a*d-b*c);}}
import java.util.Scanner;publicclassbook{publicstaticvoidmain(String[] args){
Scanner input =newScanner(System.in);
System.out.print("Enter the number of rows and columns in the array: ");int rows = input.nextInt();int columns = input.nextInt();double[][] dick =newdouble[rows][columns];
System.out.print("Enter the array: ");for(int i=0;i<rows;i++){for(int j=0;j<columns;j++)
dick[i][j]=input.nextDouble();}
Location holy =locateLargest(dick);
System.out.println("The location of the largest element is "+holy.maxValue+" at ("+holy.row+", "+holy.column+")");}publicstatic Location locateLargest(double[][] a){
Location ass =newLocation();
ass.maxValue=a[0][0];
ass.column=0;
ass.row=0;int rowCount = a.length;int columnCount = a[0].length;for(int i=0;i<rowCount;i++){for(int j=0;j<columnCount;j++){if(a[i][j]>ass.maxValue){
ass.row=i;
ass.maxValue=a[i][j];
ass.column=j;}}}return ass;}}classLocation{publicint row;publicint column;publicdouble maxValue;}