判断三角形类型 018

int main()
{
double longs, width, height;
printf("请输入三条边长度：");
scanf("%lf %lf %lf", &longs, &width, &height);
double temp = (longs + width + height) / 2;
double ret = sqrt(temp*(temp - longs) * (temp - width) * (temp - height));
if (longs + width > height && longs + height > width && width + height > longs)
{
if (longs == width && width == height && height == width)
{
printf("等边三角形 面积为:%lf", (longs*height)*0.5);
}
else if (longs == width || longs == height || width == height)
{
/*海伦公式：三角形面积S = √[P(P - A)(P - B)(P - C)]
其中P = (A + B + C) / 2
A、B、C表示三角形的边长，√表示根号，即紧跟后面的括号内的全部数开根号*/

printf("等腰三角形 面积为%lf", ret);
}
//直角三角形特征；两边的平方等于第三边的平方、
else if (longs * longs + width *width == height*height || longs *longs + height*height == width *width
|| width * width + height*height == longs*longs)
{

printf("直角三角形，面积为%lf",ret);
}
else
{
printf("普通三角形");
}

}
else
{
printf("\n不能构成三角形");
}

system("pause");
return 0;
}