#include <iostream>
#include <math.h>
int main() {
setlocale(LC_ALL, "Russian");
double a = 0;
double b = 0;
double c = 0;
double p = 0;
std::cout << "Введите три стороны треугольника\n";
std::cin >> a >> b >> c;
if ((a == b) && (b == c)) {
std::cout << "треугольник равносторонний\n";
} else if ((a == b) || (a == c) || (b == c)) {
std::cout << "треугольник равнобедренный\n";
}
if ((a + b == c) && (a + c == b) && (b + c == a)) {
std::cout << "треугольника не существует\n";
} else {
p = a + b + c;
}
double s = sqrt(p * (p - a) * (p - b) * (p - c));
std::cout << "S = " << s << '\n';
}
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