///这个前两天刚回过的

#include

#include

int main (void)

{

double a,b,c;

double delta,x1,x2;

printf("请输入a,b,c:\n");

scanf("%lf%lf%lf",&a,&b,&c);

delta = b*b - 4*c*a;

if (delta > 0)

{

x1 = (-b + sqrt(delta) ) / (2 * a);

x2 = (-b - sqrt(delta) ) / (2 * a);

printf("该一元二次方程有两个解,x1 = %lf,x2 = %lf\n",x1, x2);

}

else if (delta == 0)

{

x1 = (-b) / (2*a);

x2 = x1;

printf("该一元二次方程只有一个解, x1 = x2 = %lf\n", x1);

}

else

{

printf ("无解\n");

}

return 0;

}