1029: C语言-解方程
题目描述
求方程 的根，用三个函数分别求当b^2-4ac大于0、等于0、和小于0时的根，并输出结果。从主函数输入a、b、c的值。

输入
a b c
输出
x1=? x2=?
样例输入
4 1 1
样例输出
x1=-0.125+0.484i x2=-0.125-0.484i

# include<stdio.h>
# include<math.h>
void k(double a,double b,double m);
void kk(double a,double b,double m);
void kkk(double a,double b,double m);
int main()
{
	double a,b,c,m;
	scanf("%lf %lf %lf",&a,&b,&c);
	m=b*b-4*a*c;
	if(m>0) k(a,b,m);
	if(m==0) kk(a,b,m);
	if(m<0)  kkk(a,b,m);
	return 0;
}
void k(double a,double b,double m)
{
	printf("x1=%0.3lf x2=%0.3lf",(-b+sqrt(m))/(2.0*a),(-b-sqrt(m))/(2.0*a));
}
void kk(double a,double b,double m)
{
	printf("x1=%0.3lf x2=%0.3lf",(-b+sqrt(m))/(2.0*a),(-b-sqrt(m))/(2.0*a));
}
void kkk(double a,double b,double m)
{
	printf("x1=%0.3lf+%0.3lfi x2=%0.3lf-%0.3lfi",(-b)/(2.0*a),sqrt(-m)/(2.0*a),(-b)/(2.0*a),sqrt(-m)/(2.0*a));
}

#include<stdio.h>
#include<math.h>
void Dy(float x, float y,float z)
{
float s,p;
s=p = -y / (2 * x);
printf(“该方程的根为：%.4f,%.4f\n”, s,p);
}
void Da(float x, float y,float z,float disc)
{
float m, n;
m = (-y + sqrt(disc)) / (2 * x);
n = (-y - sqrt(disc)) / (2 * x);
printf(“该方程的根为：%.4fand%.4f\n”, m,n);
}
void Xy(float x, float y, float z, float disc)
{
float t, r;
t = -y / (2 * x);
r = sqrt(-disc) / (2 * x);
printf(“该方程的一个根为:%.4f+%.4fi\n”,t,r);
printf(“该方程的另一个根为:%4f-%4fi\n”,t, r);
}
void main()
{
float a, b, c;
printf(“请输入系数：”);
scanf("%f%f%f", &a, &b, &c);
float disc = bb - 4 * ac;
if (fabs(a) <= 1e-6)
{
printf(“该方程无根！”);
}
else if (fabs(disc) <= 1e-6)
{
Dy(a, b,c);
}
else if (disc >0)
{
Da(a,b,c,disc);
}
else if (disc < 0)
{
Xy(a,b,c,disc);
}

}

1.程序语言
#include<stdio.h>
#include<math.h>
void WT1(float a, float b, float c,float disc);
void WT2(float a, float b, float c,float disc);
void WT3(float a, float b, float c,float disc);
void main()
{
float disc;
float a, b, c, x1, x2;
printf(“请输入三个数”);
scanf("%f%f%f", &a, &b, &c);
if (fabs(a) <= 1e-6) `` //判定是否为二元一次方程；
{
printf(“不是二元一次方程，请重新输入”);
}
else
{
disc = bb - 4 * ac;

	if (fabs(disc) <=1e-6)              //有两个相等的实数根的情况
	{
		WT1(a, b, c,disc);
	}
	else if (disc > 1e-6)               //有两个不等的实数根的情况
	{
		WT2(a, b, c,disc);
	}
	else                                //有复数根的情况
	{
		WT3(a, b, c,disc);
	}
}

}
void WT1(float a, float b, float c,float disc) //定义根
{
float x1;
x1 = -b / (2 * a);
printf(“有两个相等的实数根：%8.4f\n”,x1);
}
void WT2(float a, float b, float c,float disc)
{
float x1, x2;
x1 = (-b + sqrt(disc)) / (2 * a);
x2 = (-b - sqrt(disc)) / (2 * a);
printf(“有两个不相等的实数根：%8.4f and %8.4f\n”, x1, x2);
}
void WT3(float a, float b, float c,float disc)
{
float realpart, imagpart;
realpart = -b / (2 * a);
imagpart = sqrt(-disc) / (2 * a);
printf(“有复根：\n”);
printf("%8.4f+%8.4fi\n", realpart , imagpart);
printf("%8.4f-%8.4fi\n", realpart , imagpart);
}`
2.结果演示