这是无效的使用

Question

这是我的echelleetserpent.hpp：

#include <vector>
#include <iostream>
#include <ctime>
#include <random>

#ifndef ECHELLE
#define ECHELLE

struct Player{
    int position;
    int n_step;
    Player(): position(0), n_step(0) {};
};

class SnakesAndLadders{
    private:
        int n_players;
        int n_board;
        std::vector<Player> players;
        std::vector<int> board;
    public:
        int roll_die(std::mt19937 &) const;
        bool one_step(std::mt19937 & G, int j);
        int game(std::mt19937);
};



#endif

还有我的蛇。cpp

#include "echelleetserpent.hpp"
#include <algorithm>

int SnakesAndLadders::roll_die(std::mt19937 & gen) const {
    std::uniform_int_distribution<int> U(1,6);
    int dice = U(gen);
    return dice;
}

bool SnakesAndLadders::one_step(std::mt19937 & G, int j) {
    int dice = roll_die(G);
    std::cout << "Le résultat du dé est : " << dice << std::endl;
    players[j].n_step++;
    players[j].position+=dice;
    return (players[j].position >= n_board) ? true : false;
}

int SnakesAndLadders::game(std::mt19937 G) {
    while (std::any_of(players.begin(), players.end(), [n_board](Player p) {return p.position < n_board;})) {
        for(int i=0; i<n_players; i++) {
            this->one_step(G,i);
        }
    }
    return std::min_element(this->players.begin(), this->players.end(), [n_board](Player p1, Player p2) {
        if(p1.position>=n_board and p2.position >= n_board) { return p1.position < p2.position; } else { return false; }});
}

我得到以下错误：

echelleetserpent.cpp: In member function ‘int SnakesAndLadders::game(std::mt19937)’:
echelleetserpent.cpp:60:54: error: capture of non-variable ‘SnakesAndLadders::n_board’ 
  while (std::any_of(players.begin(), players.end(), [n_board](Player p) {return p.position < n_board;})) {
                                                      ^~~~~~~
In file included from echelleetserpent.cpp:1:0:
echelleetserpent.hpp:18:7: note: ‘int SnakesAndLadders::n_board’ declared here
   int n_board;
       ^~~~~~~
echelleetserpent.cpp: In lambda function:
echelleetserpent.cpp:60:94: error: ‘this’ was not captured for this lambda function
 rs.begin(), players.end(), [n_board](Player p) {return p.position < n_board;})) {
                                                                     ^~~~~~~
echelleetserpent.cpp:60:94: error: invalid use of non-static data member ‘SnakesAndLadders::n_board’
In file included from echelleetserpent.cpp:1:0:
echelleetserpent.hpp:18:7: note: declared here
   int n_board;
       ^~~~~~~
echelleetserpent.cpp: In member function ‘int SnakesAndLadders::game(std::mt19937)’:
echelleetserpent.cpp:65:71: error: capture of non-variable ‘SnakesAndLadders::n_board’ 
 eturn std::min_element(this->players.begin(), this->players.end(), [n_board](Player p1, Player p2) {
                                                                     ^~~~~~~
In file included from echelleetserpent.cpp:1:0:
echelleetserpent.hpp:18:7: note: ‘int SnakesAndLadders::n_board’ declared here
   int n_board;
       ^~~~~~~
echelleetserpent.cpp: In lambda function:
echelleetserpent.cpp:66:19: error: ‘this’ was not captured for this lambda function
   if(p1.position>=n_board and p2.position >= n_board) { return p1.position < p2.position; } else { return false; }});
                   ^~~~~~~
echelleetserpent.cpp:66:19: error: invalid use of non-static data member ‘SnakesAndLadders::n_board’
In file included from echelleetserpent.cpp:1:0:
echelleetserpent.hpp:18:7: note: declared here
   int n_board;
       ^~~~~~~
echelleetserpent.cpp:66:46: error: ‘this’ was not captured for this lambda function
   if(p1.position>=n_board and p2.position >= n_board) { return p1.position < p2.position; } else { return false; }});
                                              ^~~~~~~
echelleetserpent.cpp:66:46: error: invalid use of non-static data member ‘SnakesAndLadders::n_board’
In file included from echelleetserpent.cpp:1:0:
echelleetserpent.hpp:18:7: note: declared here
   int n_board;
       ^~~~~~~
echelleetserpent.cpp: In member function ‘int SnakesAndLadders::game(std::mt19937)’:
echelleetserpent.cpp:66:116: error: cannot convert ‘__gnu_cxx::__normal_iterator<Player*, std::vector<Player> >’ to ‘int’ in return
 ion >= n_board) { return p1.position < p2.position; } else { return false; }});

错误继续：

在/usr/include/c/7/bits/stl_algobase中包含的文件中。h:71:0，来自/usr/include/c/7/vector:60，来自echelleetserpent。hpp:1，来自echelleetserpent。cpp:1:/usr/include/c/7/bits/predefined_ops。h:在'bool__gnu_cxx:：_ops:：_Iter_pred'的实例化中

]“/usr/include/c/7/bits/stl_algo。h:161:23:从“_iteratorstd:：_find_if（_Iterator，_Iterator，_Predicate）[with _Iterator=u gnu_cxx:：u normal_Iterator:u

Answer 1

我认为，你需要捕捉到这一点。

while (std::any_of(players.begin(), players.end(), [this](Player p) {return p.position < n_board;})) {
    for(int i=0; i<n_players; i++) {
        this->one_step(G,i);
    }
}