c++ - XCode 中忽略了段错误

Question

我在基于 Web 的编辑器中遇到此代码的段错误，但在 XCode 中却没有。我对这些错误不是很熟悉，但我查了查并无法确定问题所在。另一个区别是我在使用 Web 编辑器时删除了主要方法。有谁知道问题出在哪里？提前致谢。

#include <iostream>
#include <stdio.h>
#include <vector>
#include <string>
using namespace std;

class Lexer
{
public: vector <string> tokenize(vector <string> tokens, string input);
};

vector <string> Lexer::tokenize(vector <string> tokens, string input)
{
    vector <string> consumed;

    if(tokens.size()>50)
    {
        tokens.resize(50);
    }

    //The next section sorts the tokens from largest to smallest

    int swap_count = 0; //this tracks whether the sort needs to happen again

    do
    {
        swap_count = 0; // set the swap count to zero

        for(int i=0; i<tokens.size(); i++) //loop that runs the length of the 'tokens' string
        {
            if(tokens[i].length()<tokens[i+1].length()) // if this token is smaller in length than the next token
            {
                tokens[i].swap(tokens[i+1]); //swap the tokens
                swap_count++; //add one to the swap count
            }
        }
    }
    while(swap_count!=0); //while there are swaps

    //The next section consumes the input string.
    while(input.length()>0)
    {
        int count_tokens_consumed=0;

        for(int i=0; i<tokens.size(); i++) // loop set up to go through the units in the tokens vector
        {
            if(tokens[i]==input.substr(0,tokens[i].length())) //if the current token matches the first part of the input
            {
                consumed.push_back(tokens[i]); //add the token to the consumed vector
                input = input.substr(tokens[i].length()); //remove the token from the front of the input string
                count_tokens_consumed++;
                i=int(tokens.size());
            }
        }

        if (count_tokens_consumed==0)
        {
            input = input.substr(1);//or remove the first character on no match
        }
    }

    return consumed;
}

int main()
{
    Lexer LexerOne;
    vector <string> LexerOne_out = LexerOne.tokenize({"AbCd","dEfG","GhIj"},"abCdEfGhIjAbCdEfGhIj");
    for(vector<string>::iterator i = LexerOne_out.begin(); i != LexerOne_out.end(); ++i)

        cout << *i << " ";
    return 0;
}

Answer 1

段错误是否在一种环境中被忽略，而在另一种环境中是否被忽略是无关紧要的。
导致段错误的操作是未定义的行为。

---

下面一行代码:

line 31: tokens[i+1].length()

不是您的 token 的有效索引。
这是因为您正在从 0 迭代到 tokens.size()。
token 的有效索引范围是从 0 到 tokens.size()-1。