题解 | #计算一元二次方程#

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

int main() 
{
    float a, b, c;
    while(scanf("%f %f %f", &a, &b, &c)==3)
    {
    if (a == 0)
        printf("Not quadratic equation");
    else 
    {
        float d = b * b - 4 * a * c;
        if (d > 0)
            printf("x1=%.2f;x2=%.2f", (-b - sqrt(d)) / 2 / a, (-b + sqrt(d)) / 2 / a);
        else if (d == 0) 
        {
            if (b != 0)
                printf("x1=x2=%.2f", b / -2 / a);
            else
                printf("x1=x2=0.00");
        } 
        else
            printf("x1=%.2f%.2fi;x2=%.2f+%.2fi", -b / (2 * a), -sqrt(-d) / (2 * a),
                   -b / (2 * a), sqrt(-d) / (2 * a));
    }
    printf("\n");
    }
    return 0;
}