int a, b;
	  double c;
	  double d=1.2;
	 

Skaičių tipai

import java.io.*;
public class Prog2_1{
public static void main ( String arg[] ) throws IOException {

double d;
int m;


BufferedReader br = new BufferedReader (
new InputStreamReader (System.in)); 

System.out.println ("Iveskite naturaluji skaiciu m");
m=Integer.parseInt(br.readLine());
System.out.println ("Programa generuoja double tipo skaiciu mazesni uz "+ m);
System.out.println("Po to  perveda ji i kito tipo skaicius");
System.out.println ("Paspauskite klavisa");
br.readLine();

d=Math.random()*m;

System.out.println ("generuotas double tipo skaicius d= "+d );
System.out.println ("byte tipas d= "+(byte)d );
System.out.println ("short tipas d= "+(short)d );
System.out.println ("int tipas d= "+(int)d );
System.out.println ("long tipas d= "+(long)d );
System.out.println ("float tipas d= "+(float)d );
System.out.println ("double tipas d= "+d );
System.out.println ("char tipas d= "+(char)d );
br.readLine();

}
}

Math klasė ir jos metodai

Funkcijos reikšmių skaičiavimo programa

import java.io.*;
public class Prog2_2{
public static void main ( String arg[] ) throws IOException {

double a,b,x,y;

BufferedReader br = new BufferedReader (
new InputStreamReader (System.in)); 

System.out.println ("Iveskite skaiciu a");
a=new Double(br.readLine()).doubleValue();

System.out.println ("Iveskite skaiciu b");
b=new Double(br.readLine()).doubleValue();

System.out.println ("Funkcijos f(x)=x^2 reiksmes");
x=a;

while (x<=b){
y=x*x;	
System.out.println ("f("+x+")= "+y);
x=x+0.2;
}	
br.readLine();
}
}

Funkcijos reikšmių skaičiavimas

import java.applet.*;
import java.awt.*;
import java.awt.event.*;

public class Appl2_1 extends Applet implements ActionListener{

Label antr;	
Button mygt, mygt1;
TextField txt;

public void init() {
setLayout(new GridLayout(4,1));
antr = new Label("Funkcijos f(x)=x^2 reiksmės",Label.CENTER);
add(antr);
txt= new TextField(); 
add(txt);

mygt = new Button("Įvedę x reikšmę, paspauskite!");
mygt.addActionListener(this);
add(mygt);

mygt1 = new Button("Isvalyti ivedimo lauka");
mygt1.addActionListener(this);
add(mygt1);
}
	
public void actionPerformed(ActionEvent iv)
{
if (iv.getSource()==mygt) 
fnk();
if (iv.getSource()==mygt1) 
txt.setText("");
}
	
public void fnk()
{
double x,fx;
x=Double.valueOf(txt.getText()).doubleValue();	
txt.setText("f("+x+")="+x*x);
} 
}

Funkcijos grafikas

import java.awt.*;
import java.applet.*;

public class Appl2_2 extends Applet 
{
double a=0;
double b=2;
double h=0.1;
int pl, au;
double fmax =4;
double fmin =0;

public void init()
{
pl = getSize().width;
au=getSize().height; 	
}		

double f(double x)
{return x*x;}

public void paint(Graphics g)
{
double x=a;
int prx,pry;
int glx = (int) (pl*(x-a)/(b-a));
int gly = (int) (au*(fmax-f(x))/(fmax-fmin));

while (x<b)
{x+=h;
prx = glx;
pry=gly;
glx = (int) (pl*(x-a)/(b-a));
gly = (int) (au*(fmax-f(x))/(fmax-fmin));
g.drawLine(prx,pry,glx,gly);}
}	
}

Užduotis

1. f(x)=ax³+bsin(x);
2. f(x)=asin(bx)+bcos(ax);
3. f(x)=aln(x)+bsin(x);
4. f(x)=e ^ax+bx²;
5. f(x)=max(asin(x), bcos(x));
6. f(x)=min(asinx, bx);
7. f(x)=tg(ax)-be^x;
8. f(x)=barcsin(x)-barccos(x);
9. f(x)=min(asin(x), 1/(1+x²));
10. f(x)=arctg(ax)-arctg(bx);