Triangle

public class point{
public double x;
public double y;
public point(double x,double y){
this.x=x;
this.y=y;
}
public void setx(double nx){x=nx;}
public void sety(double ny){y=ny;}
public double getx(){return x;}
public double gety(){return y;}
public String toString(){
return"("+x+","+y+")";
}
}

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public class line{

point p1,p2;

 public line(point p1, point p2){

 this.p1=p1;

 this.p2=p2;

 }

public line(double x1,double y1,double x2, double y2){

this.p1=new point(x1,y1);

this.p2=new point(x2,y2);

}

public double getlength(){

double dx=p1.x-p2.x;

double dy=p1.y-p2.y;

return Math.round(Math.sqrt(dx*dx+dy*dy)*100)/100.0;

}

public point getp1(){return p1;}

public point getp2(){return p2;}

public void setp1(point np){p1=np;}

public void setp2(point np){p2=np;}

public void setp1(double x,double y){

p1=new point(x,y);

}

public void setp2(double x,double y){

p2=new point(x,y);

}

public String toString(){

return "line "+p1+"__"+p2+"of length "+getlength();

}

}

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public class triangle{

private point p1,p2,p3;

private double area,perimeter;

public triangle(double x1,double y1,double x2,double y2,double x3,double y3){

p1=new point(x1,y1);

p2=new point(x2,y2);

p3=new point(x3,y3);

computearea();

computeperimeter();

}

public triangle(point p1,point p2,point p3){

this.p1=p1;

this.p2=p2;

this.p3=p3;

computearea();

computeperimeter();

}

public point getp1(){return p1;}

public point getp2(){return p2;}

public point getp3(){return p3;}

public void computearea(){

double a=new line(p1,p2).getlength();

double b=new line(p1,p3).getlength();

double c=new line(p3,p2).getlength();

double s=(a+b+c)/2.0;

area=Math.sqrt(s*(s-a)*(s-b)*(s-c));

}

public void computeperimeter(){

double a=new line(p1,p2).getlength();

double b=new line(p1,p3).getlength();

double c=new line(p3,p2).getlength();

perimeter=a+b+c;

}

public double getarea(){return Math.round(area*100)/100.0;}

public double getperimeter(){return perimeter;}

public boolean isrectangledtriangle(){

double a=new line(p1,p2).getlength();

double b=new line(p1,p3).getlength();

double c=new line(p3,p2).getlength();

double tmp;

if(b>a){tmp=a;a=b;b=tmp;}

if(c>a){tmp=a;a=c;c=tmp;}

return(a*a==b*b+c*c);

}

public String toString(){

String retString="";

String arectangled="not a rectangled";

if(isrectangledtriangle()) arectangled=" a rectangled";

retString="triangle "+p1+"::"+p2+"::"+p3+"::"+"is"+arectangled+"triangle\n";

retString=retString+"and it is of aea::"+getarea()+", and primeter::"+getperimeter();

return retString;

}

}

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import javax.swing.JOptionPane;

public class triangledemo{

public static void main(String[] argc){

triangle t1=new triangle(0,0,4,4,2,3);

line l1=new line(new point(0,0),new point(4,4));

line l2=new line(new point(0,0),new point(2,3));

line l3=new line(4,4,2,3);

point A=new point(3,4);

point B=new point(6,4);

point C=new point(3,8);

triangle t2=new triangle(A,B,C);

JOptionPane.showMessageDialog(null,l1+"\n"+l2+"\n"+l3+"\n"+t1+"\n"+t2,"triangles and line",1);

}

}