题解 | #计算一元二次方程#

#include<stdio.h>
#include<math.h>
int main() {
    float a = 0, b = 0, c = 0;
    float x1, x2;
    while (scanf("%f %f %f", &a, &b, &c) != EOF) {
        //  float d=b*b-4*a*c;
        if (a == 0)
            printf("Not quadratic equation");
        else {
            float disc = b * b - 4 * a * c;
            if (disc == 0) {
                float s = -b + sqrt(disc);
                if (s == 0) {
                    printf("x1=x2=%.2f\n", s);
                } else {
                    printf("x1=x2=%.2f\n", (-b) / 2.0 / a);
                }
            } else if (disc < 0) {
                printf("x1=%.2f-%.2fi;x2=%.2f+%.2fi\n", -b / 2 / a, sqrt(-disc) / 2 / a,
                       -b / 2 / a, sqrt(-disc) / 2 / a);
            }

            else
                printf("x1=%.2f;x2=%.2f\n", (-b - sqrt(disc)) / 2.0 / a, (-b + sqrt(disc)) / 2.0 / a);
        }
    }
    return 0;

}