Modernes C++ programmieren

// https://godbolt.org/z/We3oWrcWW 
#include <iostream>
#include <cmath>     // sqrt
#include <concepts>  // floating_point
using std::min; using std::max; using std::floating_point;

template<floating_point T> T heron(T a, T b, T c) {
    auto s = (a+b+c) / 2;
    return sqrt(s*(s-a)*(s-b)*(s-c));
}

template<floating_point T> T kahan(T a, T b, T c) {
   auto x = max(a,max(b,c));
   auto y = max(min(a,b), min(max(a,b),c));
   auto z = min(a,min(b,c));
   return sqrt( (x+(y+z))*(z-(x-y))*(z+(x-y))*(x+(y-z)) )/4 ;
}

template<floating_point T> void dreieck(T a, T b, T c) {
   std::cout << "heron: " << heron(a,b,c) << '\n';
   std::cout << "kahan: " << kahan(a,b,c) << '\n';
}

int main() {
   dreieck(3.0f, 4.0f, 5.0f);
}