题解 | #计算一元二次方程#

#include <stdio.h>
#include <math.h>
int main() {
    double a, b, c;
    double x1 = 0.0;
    double x2 = 0.0;
    double real = 0.0;
    double img = 0.0;
    while (scanf("%lf %lf %lf", &a, &b, &c) != EOF) 
    {
        if (a == 0) 
        {
            printf("Not quadratic equation");
        } 
        else 
        {
            if (b * b - 4 * a * c > 0) 
            {
                x1 = (-b - sqrt(b * b - 4 * a * c)) / (2 * a);
                x2 = (-b + sqrt(b * b - 4 * a * c)) / (2 * a);
                printf("x1=%.2f;x2=%.2f\n", x1, x2);
            } 
            else if (b * b - 4 * a * c == 0) 
            {
                x1 = x2 = -b / (2 * a) == 0 ? 0.00 : -b / (2 * a);
                printf("x1=x2=%.2f\n", x1);
            } 
            else 
            {
                real = -b / (2 * a);
                img = sqrt(-b * b + 4 * a * c) / (2 * a);
                printf("x1=%.2f-%.2fi;x2=%.2f+%.2fi\n", real, img, real, img);
            }
        }
    }
    return 0;
}