展开全部

import java.io.*;

import java.util.*;public class SolveEquation

{

void print()throws IOException

{

char ch='y';

System.out.println("求解几次方程？1：一次 2：二次 3：三次");

Scanner sLine=new Scanner(System.in);

int pm=sLine.nextInt();

if(pm==1)

{

System.out.println("你选择62616964757a686964616fe78988e69d8331333332633030的是一元一次方程:");

SolveEquation.SolveSimpleEquation fc=new SolveEquation().new SolveSimpleEquation();

fc.SolveSimpleEquation();

}

else if(pm==2)

{

System.out.println("你选择的是一元二次方程:");

SolveEquation.SolveQuadraticEquation fc=new SolveEquation().new SolveQuadraticEquation();

fc.SolveQuadraticEquation();

}

else if(pm==3)

{

System.out.println("你选择的是一元三次方程:");

SolveEquation.SolveCubicEquation fc=new SolveEquation().new SolveCubicEquation();

fc.SolveCubicEquation();

}

else

{

print();

}

System.out.println("你是否想继续:(y/n)");

ch=(char)System.in.read()

System.in.skip(2);

if(ch=='y')

{

print();

}

else if(ch=='n')

{

System.out.println("Good luck!");

}

else

{

print();

}

public static void main (String args[]) throws IOException

{

SolveEquation se=new SolveEquation();

se.print();

}

interface I1

{

void SolveCubicEquation();

}

interface I2

{

void SolveQuadraticEquation();

}

interface I3

{

void SolveSimpleEquation();

}

class SolveCubicEquation implements I1

{

public void SolveCubicEquation()

{

System.out.println("请输入形如一元三次方程mx^3+nx^2+tx+s=0的四个系数");

Scanner sce=new Scanner(System.in);

double m=sce.nextDouble();

double n=sce.nextDouble();

double t=sce.nextDouble();

double s=sce.nextDouble();

if(m==0)

{

System.out.print("输入错误!");

}

else

{

double a=n/m;

double b=t/m;

double c=s/m;

double q=(a*a-3*b)/9;

double r=(2*a*a*a-9*a*b+27*c)/54;

if(r*r

{

System.out.println("此方程有三个解:");

t=Math.acos(r/Math.sqrt(q*q*q));

double x1=-2*Math.sqrt(q)*Math.cos(t/3)-a/3;

double x2=-2*Math.sqrt(q)*Math.cos((t+2*Math.PI)/3)-a/3;

double x3=-2*Math.sqrt(q)*Math.cos((t-2*Math.PI)/3)-a/3;

System.out.println("x1="+x1+","+"x2="+x2+","+"x3="+x3);

}

else

{

System.out.println("此方程只有一个解:");

int sgn=(r>=0)?1:-1;

double u=-sgn*Math.pow((Math.abs(r)+Math.sqrt(r*r-q*q*q)),1./3);

double v=(u!=0)?q/u:0;

double x1=u+v-a/3;

System.out.println("x="+x1);

}

}

}

}

class SolveQuadraticEquation implements I2

{

public void SolveQuadraticEquation()

{

System.out.println("请输入形如一元二次方程ax^2+bx+c=0的三个系数");

Scanner sce=new Scanner(System.in);

double a=sce.nextDouble();

double b=sce.nextDouble();

double c=sce.nextDouble();

if(a==0)

{

System.out.print("输入错误!");

}

else

{

double d=b*b-4*a*c;

if(d>0)

{

double x1=(-b+Math.sqrt(d))/2*a;

double x2=(-b+Math.sqrt(d))/2*a; System.out.println("有两个实根x1="+x1+","+"x2="+x2);

}

else if(d==0)

{

System.out.println("有一个实根"+(-b/2*a));

}

else if(d<0)

{

double Re=-b/(2*a);

double Im=Math.sqrt(-d)/(2*a);

System.out.println("实部="+Re+" "+"虚部="+Im);

}

}

}

}

class SolveSimpleEquation implements I3

{

public void SolveSimpleEquation()

{

System.out.println("请输入形如一元一次方程ax+b=0的两个系数");

Scanner sce=new Scanner(System.in);

double a=sce.nextDouble();

double b=sce.nextDouble();

if(a==0)

{

System.out.print("输入错误!");

}

else

{

System.out.println("方程的根是x="+(-b/a));

}

}

}

}

已赞过

已踩过<

你对这个回答的评价是？

评论

收起