题解 | 计算一元二次方程

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

int main() {
    float a,b,c;
    while (scanf("%f %f %f", &a, &b,&c) != EOF) { 
        if (a==0) printf("Not quadratic equation");
        else{
            float delta = b*b-4*a*c;
            float x1 , x2;
            if(delta == 0){
                x2 = (-b+sqrt(delta))/(2*a);
                printf("x1=x2=%0.2f\n",x2+0.0);  //要加0.0
            } 
            else if(delta > 0) {
                x1 = (-b-sqrt(delta))/(2*a), x2 = (-b+sqrt(delta))/(2*a);
                printf("x1=%.2f;x2=%.2f\n",x1,x2);
            }
            else{
                float alpha=-b/(2*a), beta = sqrt(-delta)/(2*a);
                printf("x1=%.2f-%.2fi;x2=%.2f+%.2fi\n",alpha,beta,alpha,beta);
            }
        }
    }
    return 0;
}