W5 COMPUTER PROGRAMMINING 2020 SPRING

W5 Array structures of basic variable types

W5Ex1

class W5Ex1

{

public static void main(String args[] )

{

int days_of_the_month[];

days_of_the_month=new int[12];

days_of_the_month[0]=31;

days_of_the_month[1]=28;

days_of_the_month[2]=31;

days_of_the_month[3]=30;

days_of_the_month[4]=31;

days_of_the_month[5]=30;

days_of_the_month[6]=31;

days_of_the_month[7]=31;

days_of_the_month[8]=30;

days_of_the_month[9]=31;

days_of_the_month[10]=30;

days_of_the_month[11]=31;

String s="Month April is "+days_of_the_month[3]+" days long";

System.out.println(s);

}}

public class W4Ex1A

{ public void plot(f1 f,int xmin,int xmax)

{ int x=xmin;

String sum="";

String s="";

int y=0;

while(x<=xmax)

{ y=f.func(x); // function to be plotted

int i=0;

sum="*";

while(i<y)

{ sum = " "+sum;i++;}

s+=sum+"\n";

x++;

}

IO.print(s);

}

public static void main(String arg[])

{ f1 f=new f1();

W4Ex1A w=new W4Ex1A();

w.plot(f,-10,10);

}

}

public class W4Ex1B

{ public static void main(String arg[])

{ f1 f=new f1();

W4Ex1A xx=new W4Ex1A();

xx.plot(f,-10,10);

}

}

EX2

W5Ex2.java

public class W5Ex2

{

public static int[] multiply(int a[],int b[])

{ int c[]=new int[a.length];

if(a.length!=b.length) {System.out.println("error wrong vector size!");}

else

{ for(int i=0;i<c.length;i++)

{c[i]=a[i]*b[i];}

}

return c;

}

public static void main(String[] args)

{

int a1[]={1,2,3,4,5,6};

int a2[]={1,4,9,16,25,36};

int a3[]=multiply(a1,a2);

String s="array1 output : ";

String s1="a1 =\n"+output(a1,5);

s1+="a2 = \n"+output(a2,5);

s1+="a3 = a1*a2 \n"+output(a3,5);

System.out.println(s1);

}

public static String output(int a[],int n)

{

String s1="[";

for(int i=0;i<a.length;i++)

{ s1+=String.format("%"+n+"d",a[i]);}

s1+="]\n";

return s1;

}}

W5Ex2A.java

import javax.swing.JOptionPane;

import java.util.*;

public class W5Ex2A

{

public static double[] multiply(double a[],double b[])

{ double c[]=new double[a.length];

if(a.length!=b.length) {System.out.println("error wrong vector size!");}

else

{ for(int i=0;i<c.length;i++)

{c[i]=a[i]*b[i];}

}

return c;

}

public static double[] input(int n)

{ double a[]=new double[n];

String s="";

for(int i=0;i<n;i++)

{s=JOptionPane.showInputDialog("a["+i+"] = ?");

a[i]=Double.parseDouble(s);

}

return a;

}

public static String output(double a[],int n)

{ Locale us=new Locale("us");

String s1="[";

for(int i=0;i<a.length;i++)

{ s1+=String.format(us,"%"+n+"f ",a[i]);}

s1+="]\n";

return s1;

}

public static void main(String[] args)

{ double a1[]=input(6);

double a2[]=input(6);

double a3[]=multiply(a1,a2);

String s="array1 output : ";

String s1="a1 =\n"+output(a1,5);

s1+="a2 = \n"+output(a2,5);

s1+="a3 = a1*a2 \n"+output(a3,5);

JOptionPane.showMessageDialog(null,s1);

}

}

Format Specifiers

Here is a quick reference to all the conversion specifiers supported.

SPECIFIER	APPLIES TO	OUTPUT
%a	floating point (except BigDecimal)	Hex output of floating point number
%b	Any type	“true” if non-null, “false” if null
%c	character	Unicode character
%d	integer (incl. byte, short, int, long, bigint)	Decimal Integer
%e	floating point	decimal number in scientific notation
%f	floating point	decimal number
%g	floating point	decimal number, possibly in scientific notation depending on the precision and value.
%h	any type	Hex String of value from hashCode() method.
%n	none	Platform-specific line separator.
%o	integer (incl. byte, short, int, long, bigint)	Octal number
%s	any type	String value
%t	Date/Time (incl. long, Calendar, Date and TemporalAccessor)	%t is the prefix for Date/Time conversions. More formatting flags are needed after this. See Date/Time conversion below.
%x	integer (incl. byte, short, int, long, bigint)	Hex string.

EX3

W5Ex3.java

public class W5Ex3

{

//array diecount[0] to diecount[5]

public static int[] die(int n)

{int diecount[]=new int[6];

int die=0;

for(int i=0;i<n;i++)

{die=1+(int)(6*Math.random());

diecount[die-1]++;

}

return diecount;

}

public static void main(String args[] )

{ String s=W5Ex2.output(die(6000000),10);

System.out.println(s);

}}

W5Ex3A.java

import javax.swing.*;

import java.util.*;

public class W5Ex3A

{

//array diecount[0] to diecount[5]

public static double[] die(int n)

{double diecount[]=new double[6];

int die=0;

for(int i=0;i<n;i++)

{die=1+(int)(6*Math.random());

diecount[die-1]++;

}

for(int i=0;i<6;i++)

{diecount[i]/=n;}

return diecount;

}

public static String output(double a[],int n)

{ Locale us=new Locale("us");

String s1="[";

for(int i=0;i<a.length;i++)

{ s1+=String.format(us,"%"+n+"f",a[i]);}

s1+="]\n";

return s1;

}

public static void main(String args[] )

{ String s=output(die(6000000),10);

JOptionPane.showMessageDialog(null,s);

}}

W5Ex3B.java

import javax.swing.*;

public class W5Ex3B

{ public static void main(String args[] )

{ String s=W5Ex3A.output(W5Ex3A.die(6000000),10);

JOptionPane.showMessageDialog(null,s);

}

}

EX4

public class W5Ex4

{

public static double average(double x[])

{double total=0;

int n=x.length;

int i;

for(i=0;i<n;i++)

{total+=x[i];}

return total/n;

}

public static void main(String args[] )

{ double x[]={1.2,2.3,3.3,2.1,1.2,3.4,5.6,7.8,1.2,3.2};

IO.print("average = "+average(x));

}}

import javax.swing.*;

public class W5Ex4A

{

public static double average(double x[])

{double total=0;

int n=x.length;

int i;

for(i=0;i<n;i++)

{total+=x[i];}

return total/n;

}

public static double[] input()

{ String s=JOptionPane.showInputDialog("number of data points n = ?");

int n=Integer.parseInt(s);

double a[]=new double[n];

for(int i=0;i<n;i++)

{s=JOptionPane.showInputDialog("a["+i+"] = ?");

a[i]=Double.parseDouble(s);

}

return a;

}

public static void main(String args[] )

{ double x[]=input();

System.out.println("average = "+average(x));

}}

import javax.swing.*;

public class W5Ex4B

{

public static void main(String args[] )

{ double x[]=W5Ex4A.input();

System.out.println("average = "+W5Ex4A.average(x));

}}

EX5

W5Ex5.java

import javax.swing.*;

public class W5Ex5

{

public static double standard_deviation(double x[])

{double total=0;

double xavg=W5Ex4A.average(x);

int n=x.length;

int i;

for(i=0;i<n;i++)

{total+=(x[i]-xavg)*(x[i]-xavg);}

return Math.sqrt(total/(n-1));

}

public static double[] input()

{ String s=JOptionPane.showInputDialog("number of data points n = ?");

int n=Integer.parseInt(s);

double a[]=new double[n];

for(int i=0;i<n;i++)

{s=JOptionPane.showInputDialog("a["+i+"] = ?");

a[i]=Double.parseDouble(s);

}

return a;

}

public static void main(String args[] )

{ double x[]=input();

System.out.println("average = "+W5Ex4A.average(x)+"\nstandard deviation ="+standard_deviation(x));

}}

W5Ex5A.java

import javax.swing.*;

public class W5Ex5A

{

public static void main(String args[] )

{ double x[]=W5Ex5.input();

System.out.println("average = "+W5Ex4A.average(x)+"\nstandard deviation ="+W5Ex5.standard_deviation(x));

}}

HOMEWORK EXERCISES

W5HW1

class W5HW1

{ public static void plot(int z[])

{ int x=0;

String sum="";

String s="";

int y=0;

for(int j=0;j<z.length;j++)

{ y=z[j]; // function to be plotted

int i=0;

sum="*";

while(i<y)

{ sum = " "+sum;i++;}

s+=sum+"\n";

x++;

}

IO.print(s);

}

public static void main(String arg[])

{

}

}

int i[]={9,4,1,0,1,4,9,16,25} is given plot the array by using * so that plot shape

         *

    *

 *

*

 *

    *

         *

                *

                         *

Will come as an output

Call the class and method in main method of program W4HW2.java to calculate function value for x=0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9

(hint you can use for loop to create x values)

Now call the class f3 to achive the same result, write W4HW2A.java

W5HW2 Factorial method is given below. Calculate factorial of integer numbers 1 to 10

public static long factorial(int x)

{

if( x <= 1 )

return 1;

else

return x * factorial( x - 1);

}