在使用标准向量函数时抛出 'std::bad_alloc' 的实例后调用终止

Question

我正在做一项作业，要求我们为真人游戏模拟 'elimination voting' 程序。为此，我们使用一个 class (Vote) 来记录要淘汰的玩家的名字，另一个 (Voting) 不会在任何地方实例化，因为它的成员是静态的 (我们需要他们）。选票存储在 Voting class.

内部的向量中

问题是，即使我使用 push_back 函数将选票存储在向量中，在运行程序几次后，我得到一个 std::length_error 和 what(): basic_string::_M_create。在我关闭它并重新运行后，我第一次收到如标题中的错误 (std::bad_alloc)。

有什么想法吗？我怀疑它与 vector 没有正确释放内存有关，但我不确定。

我的代码（Voting.h）：

#ifndef VOTING_H_INCLUDED
#define VOTING_H_INCLUDED

#include <vector>
#include <map>
#include "Vote.h" //ignore this one
#include "Team.h" //this one too

class Voting
{
    public:
        static vector <Vote> votes; //votes cast during voting procedure
        static map <string, int> results; //voting results (key: name, value: number of votes)
        static void votingProcess(Team &team); //the whole voting procedure
};

#endif // VOTING_H_INCLUDED

Voting.cpp:

#include <vector>
#include <map>
#include <cstdlib>
#include "Vote.h"
#include "Voting.h"

using namespace std;

vector <Vote> Voting::votes(1);  //initialize the vector for the votes

void voteCast(Team &team);

void Voting::votingProcess(Team &team)
{
    voteCast(team);
}


void voteCast(Team &team)
{
    int playerNumber = team.getNumberOfPlayers(); //number of players right now still in the team
    int votingPlayer = 0; //index of the currently voting player
    int votedPlayerIndex = -1; //index of the player to be voted for elimination
    int reasonIndex = -1; //index of the selected reason for voting
    Vote draft;  //temporary empty vote

    srand(time(NULL)); // initialize the RNG
    Voting::votes.clear(); //clear the vector of any past votes

    string reasons[4] = {"Den ta pame kala metaxi mas", "Einai ikanoteros/i apo emena kai ton/ti theoro apeili", "Den exei na prosferei kati stin omada", "Prospathei sinexeia na sampotarei tis prospatheies mas"};
    //some reasons for elimination (i've tried smaller strings and even chars and it didn't work, so don't bother)

    do
    {
        if (team.getPlayers()[votingPlayer].getAge() != 0 && team.getPlayers()[votingPlayer].getVotes() > 0)
        //if the player with index votingPlayer has not been eliminated and has still votes to cast
        {
            do
            {
                votedPlayerIndex = rand() % 11; //select a random player for elimination
                reasonIndex = rand() % 5; //select a random reason for it
            }
            while ((team.getPlayers()[votedPlayerIndex].getAge() == 0) || (votedPlayerIndex == votingPlayer) || (team.getPlayers()[votedPlayerIndex].getImmunity() == true));
            // selection continues if the selected player has already been eliminated,
            //if the selected player is the same as the voting player or if the selected player has immunity from elimination

            team.getPlayers()[votingPlayer].setVotes(team.getPlayers()[votingPlayer].getVotes() - 1); //reduce the player's available votes by 1

            draft.setVotedPlayer(team.getPlayers()[votedPlayerIndex].getName()); //write the name of the player to be voted in an empty Vote object
            draft.setReason(reasons[reasonIndex]); //and the reason too

            Voting::votes.push_back(draft);  //push the Vote obj. in the vector
        }
        else
        {
            votingPlayer++; //ignore and get to the next player
        }
    }
    while (votingPlayer < playerNumber);  //vote casting continues until every player has casted a vote
}

Vote.h:

#ifndef VOTE_H_INCLUDED
#define VOTE_H_INCLUDED

#include <string>
#include <iostream>

using namespace std;

class Vote
{
    string voted; //name of the player to be eliminated
    string reason; //reason for elimination

    public:
        Vote() { voted = ""; reason = ""; } //constructor without parameters

        Vote(string player, string reason) { voted = player; this -> reason = reason;} //constructor with parameters (this one is used)

        ~Vote() { cout << "Vote object destroyed" << endl; }; //destructor

        string getVotedPlayer() { return voted; } //getters

        string getReason() { return reason; }

        void setVotedPlayer(string player) { voted = player; }  //setters

        void setReason(string reason) { this -> reason = reason; }

        void status() { cout << "Voted player: " << voted << endl << "Reason: " << reason << endl;} //status function
};

#endif // VOTE_H_INCLUDED

Answer 1

原因是您有一个包含 4 个元素的数组（因此只有索引 0..3 是有效的）并且您允许自己使用 5 个可能的值 (0..4) 对其进行索引，其中 4 是不是有效索引。

这里是数组的定义：

字符串原因[4] = {"Den ta pame kala metaxi mas", "Einai ikanoteros/i apo emena kai ton/ti theoro apeili", "Den exei na prosferei kati stin omada", "Prospathei sinexeia na sampotarei tis prospatheies mas"};

这里是指数的选择：

reasonIndex = rand() % 5;

这是该索引的用法：

draft.setReason（原因[原因索引]）；

这就是为什么您在 basic_string::_M_create 中看到错误的原因，因为您正在复制一个您不知道实际上是字符串的值。

在设置 reasonIndex 的行中，只需将 5 更改为 4。

在使用标准向量函数时抛出 'std::bad_alloc' 的实例后调用终止

Terminate called after throwing an instance of 'std::bad_alloc' while using standard vector functions

c++

memory

memory-leaks

memory-management

out-of-memory