一元二次方程求根程序纠错

Question

程序哪里出现了问题

#include<stdio.h>
#include<math.h>
 
int main()
{
    double 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");
        printf("x1 = x2 = %lf",-(c/b));
    }
    else
    {
        disc = b*b-4*a*c;
        if(fabs(disc)<=1e-6)
        {
            printf("has two equal roots:%lf\n",-b/(2*a));
        }
        else
        {
            if(disc>1e-6)
            {
                x1 = (-b+sqrt(disc))/(2*a);
                x2 = (-b-sqrt(disc))/(2*a);
                printf("has two real roots :\nx1 = %.2lf\nx2 = %.2lf \n",x1,x2);
            }
            else
            {
                realpart = -b/(2*a);
                imagpart = sqrt(-disc)/(2*a);
                printf("has complex roots :\n");
                printf("%lf + %lfi\n",realpart,imagpart);
                printf("%lf - %lfi\n",realpart,imagpart);
            }
        }
    }
    return 0;
}

Answer 1

第8行： scanf("%lf %lf lf%",&a,&b,&c); 最后一个格式控制符：lf% 这里错了，修改为： scanf("%lf %lf %lf",&a,&b,&c); 供参考：

#include<stdio.h>
#include<math.h>

int main()
{
    double a, b, c, disc, x1, x2, realpart, imagpart;
    scanf("%lf %lf %lf", &a, &b, &c);   //scanf("%lf %lf lf%", &a, &b, &c); 修改
    printf("the equation ");
    if (fabs(a) <= 1e-6)
    {
        printf("is not a quadratic!\n");
        printf("x1 = x2 = %lf", -(c / b));
    }
    else
    {
        disc = b * b - 4 * a * c;
        if (fabs(disc) <= 1e-6)
        {
            printf("has two equal roots:%lf\n", -b / (2 * a));
        }
        else
        {
            if (disc > 1e-6)
            {
                x1 = (-b + sqrt(disc)) / (2 * a);
                x2 = (-b - sqrt(disc)) / (2 * a);
                printf("has two real roots :\nx1 = %.2lf\nx2 = %.2lf \n", x1, x2);
            }
            else
            {
                realpart = -b / (2 * a);
                imagpart = sqrt(-disc) / (2 * a);
                printf("has complex roots :\n");
                printf("%lf + %lfi\n", realpart, imagpart);
                printf("%lf - %lfi\n", realpart, imagpart);
            }
        }
    }
    return 0;
}