访问冲突写入位置动态分配数组

Question

我正在写一段代码。作为这段代码的一部分，我决定使用一个动态分配的数组来存储一组字符串。但是，当我尝试为我的数组分配一个值时，出现异常

Exception thrown at 0x50D540C9 (vcruntime140d.dll) in Glicko2.exe: 0xC0000005: Access violation writing location 0xC39903E3.

从研究这个主题来看，这个异常似乎主要出现在你尝试写入你的数组之外的时候。但是在我写它的for循环里面，应该不可能在它外面写。异常发生在

行

         posResponsesTeamNames[i] = teamName;

我的密码是

int league::matchSet()
{
    std::string currLine;
    std::string *posResponsesTeamNames = new std::string[league::numTeams];
    std::string posResponsesWon[3] = { "1","2","3" };
    team* team1;
    team* team2;
    bool successful = false;
    for (int i = 0; i < league::numTeams; i++) {
         std::string teamName = league::getName(i + 1);
         for (i = 0; i < teamName.size(); i++) {
             teamName.at(i) = toupper(teamName.at(i));
         }
         posResponsesTeamNames[i] = teamName;   
    }
    std::cout << posResponsesTeamNames[1];
roundStart:
    for (int i = 0; i < league::numMatches; i++) {
        std::cout << "for match " << i + 1 << " please enter name of first team to play: ";
        std::getline(std::cin, currLine);
        int parsed = parseText(currLine, posResponsesTeamNames);
        if (parsed == 2) {
            delete[] posResponsesTeamNames;
            prepForEnd();
            return 2;
        }
        else if (parsed == 0) {
            goto roundStart;
        }
        for (int i = 0; i < league::teams.size(); i++) {
            if (currLine == league::teams.at(i).getName()) {
                successful = true;
                team1 = &league::teams.at(i);
            }
        }
        if (successful == false) {
            std::cout << "ERROR: Invalid team name entered";
            goto roundStart;
        }
secondTeam:
        std::cout << "for match " << i + 1 << " please enter name of second team to play: ";
        std::getline(std::cin, currLine);
        parsed = parseText(currLine, posResponsesTeamNames);
        if (parsed == 2) {
            delete[] posResponsesTeamNames;
            prepForEnd();
            return 2;
        }
        else if (parsed == 0) {
            goto secondTeam;
        }
        for (int i = 0; i < league::teams.size(); i++) {
            if (currLine == league::teams.at(i).getName()) {
                successful = true;
                team2 = &league::teams.at(i);
            }
        }
        if (successful == false) {
            std::cout << "ERROR: Invalid team name entered";
            goto secondTeam;
        }
whoWon:
        std::cout << "please enter 1 if the first team won, 2 if the second team won or 3 if it was a draw: ";
        std::getline(std::cin, currLine);
        parsed = parseText(currLine, posResponsesWon);
        if (parsed == 2) {
            delete[] posResponsesTeamNames;
            prepForEnd();
            return 2;
        }
        if (parsed == 0) goto whoWon;
    }
    delete[] posResponsesTeamNames;
}

Answer 1

当您调用“new”关键字时，即调用您的 class 的构造函数。如果您的 constrictor 将您新分配的对象实例化为 null，然后在您的循环中取消对该对象的引用，则可能会造成访问冲突。如果您的限制器以允许立即解除引用（初始化为空字符串“”）的方式初始化您的对象，这可能允许您写入该“新”对象而不会发生访问冲突。

Answer 2

1    std::string currLine;
2    std::string *posResponsesTeamNames = new std::string[league::numTeams];
3    std::string posResponsesWon[3] = { "1","2","3" };
4    team* team1;
5    team* team2;
6    bool successful = false;
7    for (int i = 0; i < league::numTeams; i++) {
8         std::string teamName = league::getName(i + 1);
9         for (i = 0; i < teamName.size(); i++) {
10             teamName.at(i) = toupper(teamName.at(i));
11        }
12       posResponsesTeamNames[i] = teamName;   
13    }

假设：league::numTeams 的值为 10

在第 2 行，您正在创建一个大小为 10(league::numTeams) 的数组。

在第 7 行，创建了一个局部变量 counter i。

在第 8 行，创建一个局部变量 teamName

在第 9 行，将 0 分配给 i（在第 7 行创建）并开始循环。你在这个循环中递增它。 teamName 的大小可能超过 10(league::numTeams)。让我们假设 12.

所以i的值可能大于10(league::numTeams)。现在在第 12 行，您在 posResponsesTeamNames 的位置 i 中赋值，现在是 12。这个任务肯定会失败。

可能的解决方案：在第 9 行，使用 i，而不是使用 int j 作为局部变量 teamName

上的第二个计数器

我希望这能给你答案。

访问冲突写入位置动态分配数组

Access violation writing location dynamically allocated array

c++

dynamic-arrays

visual-c++