题解 | #计算一元二次方程#

#include <stdio.h>
#include <math.h>
int main() {
    float a, b, c;
    float n = 0.0;
    while (scanf("%f %f %f", &a, &b, &c) != EOF) {
        if (a == 0) {
            printf("Not quadratic equation\n");
        } else {
            n = b * b - 4 * a * c;
            if (n == 0) {
                if ((-b / 2 * a) == -0.00) {
                    printf("x1=x2=0.00\n"); //浮点型的-0.0 != 0.0整型的-0 == 0
                } else {
                    printf("x1=x2=%.2f\n", -b / (2 * a));//同时为分母的要打括号
                }
            } else if (n > 0) {
                printf("x1=%.2f;x2=%.2f\n", (-b - sqrt(n)) / (2 * a), (-b + sqrt(n)) / (2 * a));
            } else {
                printf("x1=%.2f-%.2fi;x2=%.2f+%.2fi\n", -b / (2 * a), sqrt(-n) / (2 * a),
                       -b / (2 * a), sqrt(-n) / (2 * a));
            }
        }
    }
    return 0;
}