java:二元一次方程ax2+bx+c=0

简述一下：

一个复数类Complex存储方程的根，一个方程类Quadratic-Equation处理方程，一个主类QuadraticEquationmain调用。
(这个Complex还是用的上次的，嘿嘿嘿，像极了爱情)

Complex类：

package num;

public class Complex {

	double a;
	double b;
	public Complex(double x,double y)
	{
		a=x;
		b=y;
	}
	public static Complex add(Complex x,Complex y)
	{
		Complex ans = new Complex(x.a+y.a,x.b+y.b);
		return ans;
	}
	public static Complex sub(Complex x,Complex y)
	{
		Complex ans = new Complex(x.a-y.a,x.b-y.b);
		return ans;
	}
	public static Complex mul(Complex x,Complex y)
	{
		Complex ans = new Complex(x.a*y.a-x.b*y.b,x.a*y.b+x.b*y.a);
		return ans;
	}
	public static Complex div(Complex x,Complex y)
	{
		Complex ans = new Complex((x.a*y.a+x.b*y.b)/(y.a*y.a+x.b*y.b),(x.a*y.b-x.b*y.a)/(y.a*y.a+x.b*y.b));
		return ans;
	}
	public static void print(Complex ans)
	{
		if(ans.b>=0)
		System.out.println(ans.a+"+"+ans.b+"i");
		else
			System.out.println(ans.a+""+ans.b+"i");
	}
}

QuadraticEquation类：

package num;

public class QuadraticEquation {
	int a;
	int b;
	int c;
	public QuadraticEquation(int x,int y,int z)
	{
		a = x;
		b = y;
		c = z;
	}
	public Complex getRoot1(QuadraticEquation x)
	{
		double a=0;double b=0;
		if(getDiscriminant(x)>=0)
		{
			a = (-x.b+Math.sqrt(getDiscriminant(x)))/2*x.a;
		}
		else 
		{
			a = -x.b/(2*x.a);
			b = Math.sqrt(-getDiscriminant(x))/(2*x.a);
		}
		Complex ans = new Complex(a,b);
		return ans;
	}
	public Complex getRoot2(QuadraticEquation x)
	{
		double a=0;double b=0;
		if(getDiscriminant(x)>=0)
		{
			a = (-x.b-Math.sqrt(getDiscriminant(x)))/2*x.a;
			
		}
		else 
		{
			a = -x.b/(2*x.a);
			b = -Math.sqrt(-getDiscriminant(x))/(2*x.a);
		}
		Complex ans = new Complex(a,b);
		return ans;
		
	}
	private int getDiscriminant(QuadraticEquation x)//用于返回二次方程的判别式：b2-4ac
	{
		int ans=0;
		ans = x.b*x.b - 4*x.a*x.c;
		return ans;
	}
}

QuadraticEquationmain类：

package num;

import java.util.Scanner;

public class QuadraticEquationmain {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner scan = new Scanner(System.in);
		QuadraticEquation x = new QuadraticEquation(scan.nextInt(),scan.nextInt(),scan.nextInt());
		Complex ans1 = x.getRoot1(x);
		Complex ans2 = x.getRoot2(x);
		ans1.print(ans1);
		ans2.print(ans2);
	}
}

小记：

相遇本是美好，每一场相遇都是可遇不可求，在茫茫人海中，彼此驻足而停留，彼此的深记，都是流年里最美好的风景。

张爱玲曾说过：“于千万人之中遇见你所要遇见的人，于千万年之中，时间的无涯的荒野里，没有早一步，也没有晚一步，刚巧赶上了，那也没有别的话可说，惟有轻轻地问一声：你好，你是？”