W4 COMPUTER PROGRAMMINING 2020 SPRING

W4 Introduction to class concept & dynamic methods

We will use the class IO, be sure that it is include in the directory you use

import java.util.Scanner;

import javax.swing.*;

class IO

{ public static void print(String s)

{JOptionPane.showMessageDialog(null,s);}

public static void Cprint(String s)

{System.out.print(s);}

public static double Dinput(String s)

{ return Double.parseDouble(JOptionPane.showInputDialog(s));}

public static int Iinput(String s)

{ return Integer.parseInt(JOptionPane.showInputDialog(s));}

public static String input(String s)

{ return JOptionPane.showInputDialog(s);}

}

W4Ex1 for

class f1

{public int func(int x)

{return x*x+2*x+1;}

}

public class W4Ex1

{ public static 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();

plot(f,-10,10);

}

}

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

book.java

public class book

{ public String name,author;

int year;

public book(String namei,String authori,int yeari)

{name=namei;author=authori;year=yeari;}

public String toString()

{String s="book name = "+name+" book author = "+author+" publication year = "+year+"\n";

return s;

}

}

W4Ex2.java

public class W4Ex2

{

public static void main(String arg[])

{ book b1=new book("heat transfer","Özışık",1976);

book b2=new book("the plaque","Camus",1987);

IO.print(""+b1+b2);

}

}

EX3

rectangle.java

public class rectangle

{ double width,length;

public rectangle(double widthi,double lengthi)

{width=widthi;length=lengthi;}

public double area()

{return width*length;}

public String toString()

{String s="width = "+width+" m length = "+length+" m area = "+area()+" m"+'\u00B2'+"\n";

return s;

}}

W4Ex3.java

public class W4Ex3

{

public static void main(String arg[])

{ rectangle k1=new rectangle(1.25,2.0);

rectangle k2=new rectangle(1.5,2.5);

IO.print(""+k1+k2);

}

}

EX4

public class f2

{public double A;

public f2(double Ai)

{A=Ai;}

public double func(double x,double y)

{double z=A*x+2.35*y;

return z;}

}

public class W4Ex4

{

public static void main(String arg[])

{ f2 z1=new f2(2.5);

f2 z2=new f2(3.0);

double x=1.2;

double y=2.2;

String s="object z1 x = "+x+" y = "+y+" z1(x,y) = "+z1.func(x,y)+" A = "+z1.A+"\n";

s+="object z2 x = "+x+" y = "+y+" z2(x,y) = "+z2.func(x,y)+" A = "+z2.A+"\n";

IO.print(s);

}

}

EX5

Box.java

public class box

{ double width,length,height;

String bcolor;

public box(double widthi,double lengthi,double heighti,String bc)

{width=widthi;length=lengthi;height=heighti;bcolor=bc;}

public double area()

{return width*length+width*height+length*height;}

public double volume()

{return length*width*height;}

public String toString()

{String s="width = "+width+" m length = "+length+" m height = "+height+" m area = "+area()+" m"+'\u00B2'+" volume = "+volume()+" m"+'\u00B3'+" color = "+bcolor+"\n";

return s;

}

}

public class W4Ex5

{

public static void main(String arg[])

{ box b1=new box(1.25,2.0,3.0,"red");

box b2=new box(1.5,2.5,3.0,"blue");

IO.print(""+b1+b2);

}}

EX 6

class f3

{public double func(double x)

{return x*x+2*x+1;}

public String toString(double x1,double x2,double dx)

{String s="";

double eps=0.000001;

for(double x=x1;x<x2+eps;x+=dx)

{s+="x="+x+"y="+func(x)+"\n";}

return s;

}

}

public class W4Ex6

{

public static void main(String arg[])

{ f3 z1=new f3();

String s="object z1\n";

s+=z1.toString(0.0,2,0.1);

IO.print(s);

}

}

HOMEWORK EXERCISES

W4HW1 : Investigate excersise W4Ex5. Write a sphere class to calculate area and volume of sphere for D=0.1 m ,0.2 m and 0.3 m

public class W4HW1

{ public static void main(String arg[])

{sphere s1=new sphere(0.1);

sphere s2=new sphere(0.2);

sphere s3=new sphere(0.3);

String s="s1 = "+s1+"s2 = "+s2+"s3 = "+s3;

IO.print(s);

}

}

W4HW2

Class f3 is given as

class f3

{public double func(double x)

{return x*x+2*x+1;}

}

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)

class f3

{public double func(double x)

{return x*x+2*x+1;}

}

public class W4HW2

{ public static void main(String arg[])

{ String s="";

f3 f=new f3();

for(double x=0.1;x<1.0;x+=0.1)

{s+="x = "+x+" y = "+f.func(x)+"\n";}

IO.print(s);

}

}

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

W4HW3

class f4

{public double func(double x,double y)

{return x*x+2*x*y+y-10;}

public String toString(double x1,double x2,double dx,double y1,double y2,double dy)

{String s="";

double eps=0.000001;

for(double x=x1;x<x2+eps;x+=dx)

{ for(double y=y1;y<y2+eps;y+=dy)

{s+="x="+x+"y="+y+"z="+func(x,y)+"\n";}

}

return s;

}

}

Class f4 is given to calculate function value for x=0.0,0.25,0.5,0.75,1.0 and y=0.0,0.25,0.5,0.75,1.0 write class W4HW3