题解 | 计算一元二次方程

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

int main() {
    float a, b, c;
    float x1, x2, x3;
    float m;
    while (scanf("%f %f %f", &a, &b, &c) != EOF) {
        if (a == 0.0)
            printf("Not quadratic equation");
        else {
            m = pow(b, 2) - 4 * a * c;
            if (m == 0.0) {
                float sum1 = (-b + sqrt(m)) / (2 * a);
                if (sum1 == -0.00)printf("x1=x2=0.00\n");
                else printf("x1=x2=%.2f\n", sum1);
            } else if (m > 0.0) {
                float sum1 = (-b + sqrt(m)) / (2 * a);
                float sum2 = (-b - sqrt(m)) / (2 * a);
                printf("x1=%.2f;x2=%.2f\n", sum2, sum1);
            } else {
                float sum1 = -b / (2 * a);
                float sum2 = sqrt(-m) / (2 * a);
                printf("x1=%.2f-%.2fi;x2=%.2f+%.2fi\n", sum1, sum2, sum1, sum2);
            }
        }
    }

    return 0;
}