7-84 1023 分段函数

#include <algorithm>
#include <cmath>
#include <cstdint>
#include <iomanip>
#include <iostream>
#include <limits>
#include <numeric>
#include <string>
#include <unordered_map>
#include <utility>
#include <vector>

using i32 = std::int32_t;
using i64 = std::int64_t;
using u32 = std::uint32_t;
using u64 = std::uint64_t;
using pii = std::pair<i32, i32>;
using pll = std::pair<i64, i64>;
using vi = std::vector<i32>;
using vll = std::vector<i64>;
using vpii = std::vector<pii>;
using vpll = std::vector<pll>;

void solve();

int main()
{
    std::cin.tie(nullptr)->sync_with_stdio(false);
    solve();
}

double f(double x)
{
    if (x < 0)
    {
        return (x + 1) * (x + 1) + 2 * x + 1 / x;
    }
    return std::sqrt(x);
}

void solve()
{
    double x;
    while (std::cin >> x)
    {
        std::cout << "f(" << std::fixed << std::setprecision(2) << x << ")=";
        std::cout << std::fixed << std::setprecision(2) << f(x) << std::endl;
    }
}