分段使用Linux时出现故障，但不在Xcode中 [英] Segmentation Fault when using Linux, but not in Xcode

问题描述

我在Linux环境中运行我的代码时遇到问题。但是，它与Xcode运行完美。我使用gdb backtrace来定位我的问题，它指向一行代码，其中我设置一个节点的entry字段（字符串）等于从文本文件（也是字符串）读取的行。我有一种感觉，我不包括东西或我包括错了的东西。我在路上我的头，因为我刚刚开始c ++本月。请帮助！

I am having issues running my code in a Linux environment. However, it runs perfectly with Xcode. I have used gdb backtrace to pin-point where my problem is and it points to a line of code where I am setting a node's "entry" field (a string) equal to a line read from a text file (also a string). I have a feeling I am not including something or I am including the wrong thing. I am in way over my head since I have just started c++ this month. Please help!

#include <iostream>
#include <fstream>      // for reading dictionary.txt
#include <cstdlib>      // for rand() and srand()
#include <time.h>       // for time
#include <string>       // for string

using namespace std;

...

struct node
{
    string entry;       // stores the dictionary entry
    node *next;         // stores pointer to next node in list
};
node *head = NULL;

...

ifstream dictionary;
dictionary.open(filename);
string line;
if (dictionary.is_open())
{
    while (getline(dictionary,line))
    {
        if (head == NULL)
        {
            node *temp = new node;
            temp = (node*)malloc(sizeof(node));
            temp->entry = line;    // this is where I segfault according to backtrace
            temp->next = NULL;
            head = temp;
        } // if first entry

...
获取使用gdb：

... and the error I get using gdb:

编程接收信号SIGSEGV，分段故障。
0x0000003ce2a9d588 in std :: basic_string< char，std :: char_traits< char>，std :: allocator< char> > :: assign（std :: basic_string< char，std :: char_traits< char>，std :: allocator< char>> const&）
（）from /usr/lib64/libstdc++.so.6

Program received signal SIGSEGV, Segmentation fault. 0x0000003ce2a9d588 in std::basic_string<char, std::char_traits<char>, std::allocator<char> >::assign(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) () from /usr/lib64/libstdc++.so.6

 解决方案 

推荐答案


temp =（node *）malloc（sizeof（node））;


为什么是第二行？这是你的问题的根源。当您使用 malloc ed内存与C ++对象时，不会初始化对象。删除第二行，一切都应该很好。

Why the second line? That's the source of your problem. When you use malloced memory with C++ objects, objects are not initialized. Remove the second line and all should be well.

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