题解 | #计算一元二次方程#

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

int main() {
    float a = 0;
    float b = 0;
    float c = 0;
    float x1 = 0;
    float x2 = 0;
    while (scanf("%f%f%f", &a, &b, &c) != EOF) {
        float d = -b / (2.0 * a);
        float det = b * b - 4.0 * a * c;
        if (a == 0)
            printf("Not quadratic equation");
        else {
            if (det == 0) {
                x1 = -b / (2.0 * a);
                x2 = -b / (2.0 * a);
                if (x1 != 0)
                    printf("x1=x2=%.2f", x1);
                else
                    printf("x1=x2=0.00");
            } else if (det > 0) {
                x1 = -b / (2.0 * a) - sqrt(det) / (2.0 * a);
                x2 = -b / (2.0 * a) + sqrt(det) / (2.0 * a);
                printf("x1=%.2f;x2=%.2f", x1, x2);
            } else {
                x1 = sqrt(-det) / (2.0 * a);
                x2 = sqrt(-det) / (2.0 * a);
                printf("x1=%.2f-%.2fi;x2=%.2f+%.2fi", d, x1, d, x2);
            }
        }
        printf("\n");
    }
    return 0;
}

主要是注意括号怎么打和情况怎么分