Category : tuples

I am going through the custom implementation for tuples , which is described in C++ template second edition. I need a help to undestand how the pushFront actually work. What are the steps that compiler does in order to put the new element in the start of the tuple template<typename… Elements> class Typelist { }; ..

Read more

I have a rather complex ordered internal Grammar representation of my productions consisting of typed std libarary classes: class Grammar { std::tuple<int, NonTerminal, std::vector<std::vector<Symbol>>> productions; } Now I would like to create LR0-Items from this representation. From inner to outer: std::vector<Symbol> represents a rule std::vector<std::vector<Symbol>> represents an alternative rule of the production. NonTerminal, std::vector<std::vector<Symbol>>> represents ..

Read more

I am trying to write a code that invokes a lambda with input arguments extracted from a variadic set of tuples. However, my attempt does not compile: #include <iostream> #include <tuple> #include <utility> #include <type_traits> template <typename …> struct first_of; template <typename T, typename … Args> struct first_of<T, Args…> { using type = std::decay_t<T>; }; ..

Read more

std::vector<std::tuple<PCWSTR, PCWSTR,PCWSTR> > tempVector; tempVector.push_back({ L"temp", L"temp1", L"temp2" }); tempVector.push_back({ L"data", L"data1", L"data2" }); const ULONG fieldCount = tempVector.size(); PCWSTR fieldNames = new PCWSTR[fieldCount]; PCWSTR fieldValues = new PCWSTR[fieldCount]; PCWSTR fieldSize = new PCWSTR[fieldCount]; int index=0; for (std::vector<std::tuple<PCWSTR, PCWSTR, PCWSTR>>::iterator it = tempVector.begin(); it != tempVector.end(); ++it) { fieldNames[index] = it->_Myfirst;// I know this is ..

Read more

I was curious to see whether sorting a vector <vector<int>> would be slower than sorting a vector <array <int, 3>>. The dimensions of the vector is 1000000 by 3, and below is my driver code implementing this: #include <iostream> #include <fstream> #include <cmath> #include <algorithm> #include <vector> using namespace std; int main() { vector <vector<int>> ..

Read more