题解 | #一元二次方程#
计算一元二次方程
http://www.nowcoder.com/practice/7da524bb452441b2af7e64545c38dc26
#include<stdio.h>
#include<math.h>
int main()
{
double a = 0.0;
double b = 0.0;
double c = 0.0;
while (scanf("%lf %lf %lf", &a, &b, &c) != EOF)
{
if (a == 0)
{
printf("Not quadratic equation\n");
}
else
{
double deta = b * b - 4 * a * c;
if (deta == 0)
{
if (a < 0)
{
printf("x1=x2=%.2lf\n", (-b - sqrt(deta)) / (2 * a));//因为测试用例4 0 0会输出-0.00 所以加一个判断条件
}
else
{
printf("x1=x2=%.2lf\n", (-b + sqrt(deta)) / (2 * a));
}
}
else if (deta > 0)
{
printf("x1=%.2lf;x2=%.2lf\n", ((-b - sqrt(deta)) / (2 * a)), ((-b + sqrt(deta)) / (2 * a)));
}
else
{
double real = -b / (2 * a);
double image = sqrt(-deta) / (2 * a);
if (image < 0)//测试用例的 -1 5 -10 会出现 -- +- 所以加判断条件 把-号消掉
{
image = (-image);
}
printf("x1=%.2lf-%.2lfi;x2=%.2lf+%.2lfi\n", real, image, real, image);
}
}
}
return 0;
}
