C++ memo

test.cpp

#include <iostream>
#include <vector>
#include <initializer_list>
#include <type_traits>
#include <algorithm>
using namespace std;

template <typename T,size_t n=0>
vector<enable_if_t<is_arithmetic<T>::value,T>> data(){
    size_t x=n;
    vector<T> v;
    while(x--)v.insert(v.begin(),x);
    return v;
}
    
int main(){
    vector<int> v1=data<int,50>();
    auto it1 = upper_bound(v1.begin(), v1.end(), 9);
    cout << "pos = " << (it1 - v1.begin()) << endl;
    
    vector<int> v=data<int,5>();
    auto it = upper_bound(v.begin(), v.end(), 9);
    cout << "pos = " << (it - v.begin()) << endl;
    

    return 0;
}