刚学编程没多久求多指点 - 编程论坛

风过无痕19892020-10-30 03:00

回复楼主野猪佩奇

程序代码：

#include<stdio.h>
#include<math.h>
#define EXP 0.00000001           // 由于精度的原因，float、double类型不能比较大小
int main()
{
     double a = 0.0;
     double b = 0.0;
     double c = 0.0;
     double disc,p,q;
     scanf_s("%lf%lf%lf",&a,&b,&c);
     if((a >= -EXP) && (a <= EXP))
     {
        printf("不是一元二次方程\n");
     }
     else
    {
        disc = b * b - 4 * a * c;
     }

    p = - b / (2 * a);
    q = sqrt(disc)) / (2 * a);
    if((disc >= - EXP) && (disc <= EXP))
    {
        printf("有两个相同的实根：x = %.2lf\n",p);
    }
    else if(disc > 0.0)
    {
        printf("x1 = %.2lf  x2 = %.2lf\n",p + q,p - q);
    }
    else
    {
        printf("有两个共轭的复根: %.2lfi  %.2lfi\n",p + q,p - q);
    }

    return 0;
}

几个一2020-10-30 21:21

#include<stdio.h>
#include<math.h>
int main()//  realpare imapart分别是复根的实部虚部
{double q,a,b,c,disc,x1,x2,realpart,imagpart;
scanf("%lf%lf%lf",&a,&b,&c);
printf("The equation");
if(fabs(a)<=1e-6)
printf("is not a quadratic\n");
else
{
    disc=b*b-4*a*c;
    if(fabs(disc)<=1e-6)
        printf("has two equal roots:%8.2\n",-b/(2*a));
    else
        if(disc>1e-6)
        {x1=(-b+sqrt(disc))/(2*a);
        x2=(-b-sqrt(disc))/(2*a);
        if(x2>x1)
        {q=x2;x2=x1;x1=q;}
        else printf("x1>x2");
        printf("has distinct real roots:%8.2f and %8.2f\n",x1,x2);
        }
        else
        {
            realpart=-b/(2*a);
            imagpart=sqrt(-disc)/(2*a);
            printf("has two complex roots:\n");
            printf("%8.2f+%8.2f\t",realpart,imagpart);
            printf("%8.2f-%8.2f\n",realpart,imagpart);}
}
return 0;
}

[此贴子已经被作者于2020-10-31 19:15编辑过]