循环向量退出并出现错误进程以退出代码 -1073741819 完成

Posted 2023-02-21

【中文标题】循环向量退出并出现错误进程以退出代码 -1073741819 完成

【英文标题】：Loop over vector exits with error Process finished with exit code -1073741819

【发布时间】：2020-07-19 10:33:50

【问题描述】：

LE：如果它有任何相关性，我正在使用 CLion。该程序不打印任何内容。

我需要处理一个包含name card_type 形式的字符串向量的向量，并按字母顺序显示所有卡片以及每张卡片的实例数。输出应该类似于：

a_card 1
mastercard 4
visa 3

到目前为止，我的代码以错误Process finished with exit code -1073741819 退出。有什么问题？

#include <iostream>
#include <vector>
#include <string>

void stats(const std::vector<std::vector<std::string>>& vec) 
    std::vector<std::pair<std::string, int>> orderedCards;

    for (const auto& client : vec) //scan database for cards and make ordered vector of pairs
        if (orderedCards.empty()) //insert first pair to empty vector
            orderedCards.push_back(std::make_pair(client[1],1));

        else //for each new client scan vector and add new client/increment counter
        
           for (auto pair = orderedCards.begin(); pair != orderedCards.end(); ++pair)
               if (client[1][0] < pair->first[0]) //compare first letter of new client and existing client
                   orderedCards.insert(pair, std::make_pair(client[1], 1));// if its smaller, insert in front
                   break;// break iteration and go for next client

                else if (client[1] == pair->first) //if theyre the same, increment counter
                   pair->second+=1;
                   break;

                else if (pair+1 == orderedCards.end()) //if end is reached, there was no existing client thus add new one with high letter
                   orderedCards.push_back(std::make_pair(client[1], 1));
           
        
    
    
    for (const auto& count : orderedCards)
        std::cout<<count.first<<" "<<count.second<<std::endl; //print on each line card and counter



std::vector<std::vector<std::string>> dataBase;


int main()

    dataBase="name", "bankcard","name", "visa","name", "bankcard","name", "mastercard","name", "bankcard","name", "visa";
    
    stats(dataBase);

    return 0;

【问题讨论】：

您是否使用调试器运行您的代码？

你的迷恋在` for (auto pair = orderedCards.begin(); pair != orderedCards.end(); ++pair) ` 在第二次迭代中，你可以看到你的代码@ 987654321@可以在那里调试

你的核心转储是因为你使用了迭代器，想想你插入一个元素后迭代器会发生什么？ here 阅读关于有效性的部分

考虑使用 find 函数或它的一些变体，或者你可以使用 std::map，它的比较器使用字母顺序然后 insert 将按顺序插入

这是你代码的当前输出？ bankcard 3 mastercard 1 visa 3 ?

【参考方案1】：

@xampierre 这里是一个更简单的函数，不使用 std::sort 和算法库

void stats(const std::vector<std::vector<std::string>>& vec)


    std::map<std::string, int> orderedCards;
    for(auto & client : vec)
    
        auto it = orderedCards.insert(std::make_pair(client[1],1));
        
        if (!it.second) // this means that the key was already in the map
            it.first->second+=1;
    
    
   for (const auto& count : orderedCards)
        std::cout<<count.first<<" "<<count.second<<std::endl; //print on each line card and counter

【参考方案2】：

感谢@yaodav，我从迭代器切换到地图和排序算法。更新代码和解释：

#include <iostream>
#include <vector>
#include <string>

bool compare(const std::pair<std::string , int>& pair1, const std::pair<std::string , int>& pair2)
    return pair1.first[0] < pair2.first[0];


void stats(const std::vector<std::vector<std::string>>& vec) 
        std::map<std::string, int> map;

    for (const auto& client : vec) //scan database for cards and make map
        auto ret = map.insert(client[1], 1);// insert new key:value pair

        if (!ret.second) // this means that the key was already in the map
            ret.first->second+=1; // dereferance pointer to key to access value and +=1
    

    std::vector<std::pair<std::string, int>> orderedCards(map.begin(), map.end()); // make vector of pairs (key, value)
    std::sort(orderedCards.begin(), orderedCards.end(), compare); // sort vector according to defined compare

    for (const auto& count : orderedCards)
        std::cout<<count.first<<" "<<count.second<<std::endl;



std::vector<std::vector<std::string>> dataBase;


int main()

    dataBase="name", "bankcard","name", "visa","name", "bankcard","name", "mastercard","name", "bankcard","name", "visa";
    
    stats(dataBase);