overloading.cpp

#include <algorithm>
#include <vector>

static bool operator<=(const std::vector<double>& v, const double c)
{
    return std::ranges::all_of(v, [&c](const double& e) { return e <= c; });
}

static bool operator>=(const std::vector<double>& v, const double c)
{
    return std::ranges::all_of(v, [&c](const double& e) { return e >= c; });
}

#include <cassert>

int main()
{
    const std::vector<double> V{1, 2, 3};
    // operator<=
    assert(V <= 4);
    assert(V <= 3);
    assert(!(V <= 2));

    // operator>=
    assert(V >= 0);
    assert(!(V >= 5));
}