Giải bài tập

**Admin** Fri Sep 19, 2014 4:14 pm

Chương 2:

Bài 1: lớp Điểm

Code:: import java.lang.Math; import java.util.Scanner; public class Diem{ private int x,y; public Diem(){ x=y=0; } public Diem(int h,int t){ x=h; y=t; } public void nhapXY(){ Scanner sc = new Scanner(System.in); System.out.print("Nhap hoanh do x: "); x=sc.nextInt(); System.out.print("Nhap hoanh do y: "); y=sc.nextInt(); } public void inXY(){ System.out.println("Toa do (x,y): "+"("+x+","+y+")"); } public int getX(){ return x; } public void setX(int x){ this.x=x; } public int getY(){ return y; } public void setY(int x){ this.y=y; } public static float getDistance1(int x1, int y1, int x2, int y2){ float r; r=(float)Math.sqrt((float)Math.pow(x1-x2,2)+(float)Math.pow(y1-y2,2)); return r; } public static float getDistance2(Diem A, Diem B){ float r; r=(float)Math.sqrt((float)Math.pow(A.x-B.x,2)+(float)Math.pow(A.y-B.y,2)); return r; } public static void main(String args[]){ Diem A = new Diem(); A.inXY(); Diem B = new Diem(8,1); B.inXY(); float R1 = Diem.getDistance1(A.x, A.y, B.x, B.y); System.out.println("Khoang cach tu diem A toi diem B la: "+R1); float R2 = Diem.getDistance2(A,B); System.out.println("Khoang cach tu diem A toi diem B la: "+R2); } }

Bài 2: lớp Phương trình bậc 2

Code:: import java.util.Scanner; public class PTB2{ private int a,b,c; public PTB2(int a, int b, int c){ this.a = a; this.b = b; this.c = c; } public void nhapABC(){ Scanner sc = new Scanner(System.in); System.out.print("Nhap a: "); a = sc.nextInt(); System.out.print("Nhap b: "); b = sc.nextInt(); System.out.print("Nhap c: "); c = sc.nextInt(); } public void inABC(){ System.out.println("a="+a+","+"b="+b+","+"c="+c); } public void giaiPTB2(){ float delta =(float)Math.pow(this.b,2)-4*this.a*this.c; if(delta<0) System.out.println("Phuong trinh vo nghiem"); else if(delta==0){ float r =-this.b/(2*this.a); System.out.print("Phuong trinh co 1 nghiem: "+r); } else{ float r1= -this.b+(float)Math.sqrt(delta)/(2*this.a); float r2= -r1; System.out.print("Phuong trinh co 2 nghiem phan biet la: "+r1+","+r2); } } public static void main(String args[]){ PTB2 a = new PTB2(1,2,-3); a.nhapABC(); a.inABC(); a.giaiPTB2(); } }