题解 | #计算一元二次方程#

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