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c++ - 命令 push_back 导致退出代码 -1073741819 (0xC0000005) c++

问题描述

我正在尝试使用 c++ 制作一个小游戏，我必须将角色从地图上的一个点移动到另一个点。当我尝试通过 push_back 执行此操作然后从源点擦除时，我得到了这个退出代码。我究竟做错了什么？我的移动代码是：

void Game::move(const GridPoint & src_coordinates, const GridPoint & dst_coordinates) {
    if(checkIfLegalCell(this, src_coordinates) == false ||
       checkIfLegalCell(this, dst_coordinates) == false) {
        throw IllegalCell();
    }
    if(searchInGrid(this->grid_characters, src_coordinates) == false){
        throw CellEmpty();
    }

    std::vector<Pair>::iterator it_src=this->grid_characters.begin();
    for(;it_src != this->grid_characters.end() ; ++it_src){
        if((*it_src).grid_point == src_coordinates){
            break;
        }
    }

    if( ((*it_src).character)->checkIfCanMove(src_coordinates, dst_coordinates) == false) {
        throw MoveTooFar();
    }

    if(searchInGrid(this->grid_characters, dst_coordinates) == true){
        throw CellOccupied();
    }

    this->grid_characters.push_back(Pair(dst_coordinates,(*it_src).character));
    this->grid_characters.erase(it_src);

}

我的主要看起来像这样：

#include <iostream>

#include <cassert>

#include "Exceptions.h"
#include "Game.h"

using namespace mtm;

void example1() {
    std::cout << "------example 1------" << std::endl;
    Game g1(8,8);
    g1.addCharacter(GridPoint(1,1), Game::makeCharacter(CharacterType::MEDIC, Team::POWERLIFTERS, 10, 2, 4, 5));
    g1.addCharacter(GridPoint(1,4), Game::makeCharacter(CharacterType::SNIPER, Team::POWERLIFTERS, 10, 2, 4, 5));
    g1.addCharacter(GridPoint(6,1), Game::makeCharacter(CharacterType::SOLDIER, Team::CROSSFITTERS, 10, 2, 4, 5));
    g1.addCharacter(GridPoint(6,4), Game::makeCharacter(CharacterType::MEDIC, Team::CROSSFITTERS, 10, 2, 4, 5));
    std::cout << g1 << std::endl;
    g1.move(GridPoint(1,1), GridPoint(1,2));
    std::cout << g1 << std::endl;
    std::cout << "Nice!" << std::endl;
}

int main() {
    example1();

    return 0;
}

它打印：

C:\Users\User\CLionProjects\gameMakerCurr.1\cmake-build-debug\ex0.exe
------example 1------
*****************
| | | | | | | | |
| |M| | |N| | | |
| | | | | | | | |
| | | | | | | | |
| | | | | | | | |
| | | | | | | | |
| |s| | |m| | | |
| | | | | | | | |
*****************

Process finished with exit code -1073741819 (0xC0000005)

这是我用来创建对的“游戏”的一部分-（坐标，字符）

struct Pair {
        GridPoint grid_point;
        std::shared_ptr<Character> character;
        Pair(GridPoint grid_point, std::shared_ptr<Character> character) :
                grid_point(grid_point), character(character) {}
    };

    class Game {
        std::vector<Pair> grid_characters; //  character by grid point ; key = grid_point ; value = character.
        int height;
        int width;

有关如何解决此问题的任何提示？

标签： c++methodsmemory-managementexit

解决方案

如果你仔细看，在程序中你试图将角色推到最后：

    this->grid_characters.push_back(Pair(dst_coordinates,(*it_src).character));
    this->grid_characters.erase(it_src);

首先，在向量中推入一个新元素后，它可能会重新分配数据以有足够的容量来容纳更多元素。因此，在 push_back 之后，向量将数据移动到内存中的新位置。之后，尝试使用仍然指向 push_back 之前的位置的 it_src 进行擦除。
因此，在执行此操作之前以及计算 it_src 之前，您必须确保 vector 有足够的容量并且不会重新定位您的数据

   if (this->grid_characters.capacity() <= this->grid_characters.size())
       this->grid_characters.reserve(this->grid_characters.size() + 10);
       //other variants
       //this->grid_characters.reserve(this->grid_characters.size() + 1);
       //this->grid_characters.reserve(this->grid_characters.size() * 2);

那应该可以解决故障。


但从逻辑上讲，您为什么要尝试将对象移动到最后？您将坐标从 1,1 更改为 1,2。在向量中，它将位于坐标为 6,4 的对象之后。看起来向量中的顺序无关紧要。如果对象的顺序没有多大意义，那么只改变坐标而不在向量内移动它是有意义的

    it_src->grid_point = dst_coordinates;

如果订单很重要，请使用 set。

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