template argument was not declared in this scope - c++

Question

Why am I having issues compiling this in g++ 4.8.5, -std=c++11 -O2 -lm?
#include <algorithm>
#include <array>
#include <iostream>
#include <iterator>
#include <numeric>
#include <sstream>
#include <utility>
template<uint_fast32_t N>
class Jollo
{
private:
template<uint_fast32_t c>
struct Player
{
int_fast32_t cards[c]; // This line is OK!
uint_fast32_t nsize = c; // error 'c' was not declared in this scope
friend std::istream& operator>>(std::istream& is, Player& p)
{
for(auto& i : p.cards){
is >> i;
}
return is;
}
};
private:
enum JP_ID{ JPID_PRINCE = N+1, JPID_PRINCESS, JPID_NONE };
Player<2> m_Prince;
Player<3> m_Princess;
int_fast32_t deck[N];
constexpr static int_fast32_t RoundsToWin {2};
int_fast32_t NextAvailableCard(const JP_ID& idPlayer, int_fast32_t lastPlayedCard = 0);
public:
Jollo<N>(){
static_assert( N>4, "Invalid deck size - JolloManager");
}
bool Read();
int_fast32_t GetWinningCard();
};
template<uint_fast32_t N>
bool Jollo<N>::Read()
{
static std::string line;
std::getline(std::cin, line);
std::istringstream issline(line);
issline >> m_Princess;
issline >> m_Prince;
return (m_Princess.cards[0] != 0);
}
template<uint_fast32_t N>
int_fast32_t Jollo<N>::NextAvailableCard(const JP_ID& idPlayer, int_fast32_t lastPlayedCard)
{
if(idPlayer == JPID_PRINCE)
{
for(int_fast32_t i{0}; i<m_Prince.nsize; ++i) {
if(deck[m_Prince.cards[i] - 1] != JPID_PRINCE){
deck[m_Prince.cards[i] - 1] = JPID_PRINCE;
return m_Prince.cards[i];
}
}
} else
if(idPlayer == JPID_PRINCESS)
{
for(int_fast32_t i{0}; i<m_Princess.nsize; ++i) {
if(deck[m_Princess.cards[i] - 1] != JPID_PRINCESS && deck[m_Princess.cards[i] - 1] > lastPlayedCard) {
deck[m_Princess.cards[i] - 1] = JPID_PRINCESS;
return m_Princess.cards[i];
}
}
//no card was higher, return lowest available card
for(int_fast32_t i{0}; i<m_Princess.nsize; ++i) {
if(deck[m_Princess.cards[i] - 1] != JPID_PRINCESS) {
deck[m_Princess.cards[i] - 1] = JPID_PRINCESS;
return m_Princess.cards[i];
}
}
}
for(uint_fast32_t i{0}; i<N; i++)
{
if(deck[i] != JPID_PRINCE && deck[i] != JPID_PRINCESS && deck[i] > lastPlayedCard ) {
return deck[i];
}
}
return -1;
}
template<uint_fast32_t N>
int_fast32_t Jollo<N>::GetWinningCard()
{
std::iota(deck, deck + N, 1);
std::sort(m_Prince.cards, m_Prince.cards + m_Prince.nsize, std::greater<int_fast32_t>());
std::sort(m_Princess.cards, m_Princess.cards + m_Princess.nsize);
int_fast32_t princeWins {0};
int_fast32_t princessWins {0};
for(int_fast32_t round {0}; round < RoundsToWin; ++round) //play two first rounds
{
int_fast32_t princeCard = NextAvailableCard(JPID_PRINCE);
int_fast32_t princessCard = NextAvailableCard(JPID_PRINCESS, princeCard);
if(princessCard > princeCard){
++princessWins;
} else {
++princeWins;
}
}
int_fast32_t lastPrincessCard = NextAvailableCard(JPID_PRINCESS); //important to flip the last card on the deck before continuing
if(princessWins == RoundsToWin){
return -1;
}
if(princeWins == RoundsToWin){
return NextAvailableCard(JPID_NONE);
}
return NextAvailableCard(JPID_NONE, lastPrincessCard);
}
int main()
{
Jollo<52u> jollo;
while(true)
{
if(!jollo.Read()) {
break;
}
std::cout << jollo.GetWinningCard() << '\n';
}
return 0;
}
I can compile it on almost any other g++ version with c++11 flags.

Answer 1

This would seem to be GCC bug 57887, which seems to have been fixed in 4.9.0. I would suggest updating your compiler to something remotely not ancient…
If you cannot update your compiler for some reason (you really should update your compiler), a workaround would seem to be to avoid the in-class member initializer and use the constructor's initializer list instead:
class Jollo
{
private:
template<int c>
struct Player
{
int cards[c];
int nsize;
Player() : nsize(c) {}
};
};
working example here