自定义函数求一元二次方程

解题思路:废话不多说，直接看代码

注意事项:▲ < 0 时，方程没有实数根，但是会有2个共轭复根

参考代码:

#include<stdio.h>

#include<math.h>

void q_gen(double a, double b, double c)

{

double x1 = 0, x2 = 0;

double t = pow(b, 2) - 4 * a * c;

if (t > 0)

{

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

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

printf("x1=%.3lf x2=%.3lf\n", x1, x2);

}

else if (t == 0)

{

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

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

printf("x1=%.3lf x2=%.3lf\n", x1, x2);

}

else

{

double m, n;

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

n = sqrt(-t) / (2 * a);

printf("x1=%.3lf+%.3lfi x2=%.3lf-%.3lfi", m, n, m, n);

//printf("x1 = %.3lf+%.3lfi x2 = %.3lf-%.3lf\n", (-b) / (2 * a), sqrt(-t) / (2 * a), (-b) / (2 * a), sqrt(-t) / (2 * a));

}

}

int main()

{

double a, b, c;

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

q_gen(a, b, c);

return 0;

}