题解 | #计算三角形的周长和面积#

#include<iostream>
#include<iomanip>
#include<cmath>
using namespace std;

int main()
{
	double a, b, c;
	std::cin >> a >> b >> c;
	double C, s;
	C = a + b + c;
	double p;
	p = C / 2.0;
	s = sqrt(p * (p - a) * (p - b) * (p - c));
	std::cout << setiosflags(ios::fixed);
	std::cout << setprecision(2) << "circumference=" << C << " area=" << s;

	return 0;
}