#include <iostream> #include <cmath> #include <cstdio> using namespace std; double area(double a,double b,double c){ double p=(a+b+c)/2.0; return sqrt(p*(p-a)(p-b)(p-c)); } int main() { double a,b,c; cin>>a>>b>>c; printf("%.2f",area(a,b,c)); return 0; }

需要导入<iomanip>哦，或者像我一样，用万能头<bits/stdc++.h>

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