向量下标超出范围错误，C++
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Vector subscript out of range error, C++
提问by charli
When I try to run this program I get an error that halts the program and says, "Vector subscript out of range"
当我尝试运行这个程序时，我收到一个错误，该错误会停止程序并显示“向量下标超出范围”
Any idea what I'm doing wrong?
知道我做错了什么吗？
#include <vector>
#include <string>
#include <iostream>
#include <iomanip>
#include <fstream>
#include <sstream>
using namespace std;
//(int argc, char* argv[]
int main()
{
fstream bookread("test.txt");
vector<string> words;
bookread.open("test.txt");
if(bookread.is_open()){
cout << "opening textfile";
while(bookread.good()){
string input;
//getline(bookread, input);
bookread>>input;
//string cleanedWord=preprocess(input);
//char first=cleanedWord[0];
//if(first<=*/
//cout << "getting words";
//getWords(words, input);
}
}
cout << "all done";
words[0];
getchar();
}
回答by Axel Gneiting
You never insert anything into the words vector, so the line words[0];is illegal, because it accesses the first element of it, which does not exist.
你永远不会在 words 中插入任何东西vector，所以该行words[0];是非法的，因为它访问了它的第一个元素，它不存在。
回答by dma
I don't see where you're pushing anything on to the vector. If the vector is empty, subscript 0 would be out of range.
我看不出你在哪里将任何东西推到向量上。如果向量为空，则下标 0 将超出范围。
回答by quamrana
It seems that your program never gets round to adding anything to the vector, usually done with push_back(), so at run-time words[0]produces your subscript out of rangeerror.
似乎您的程序永远不会向向量添加任何内容，通常使用 完成push_back()，因此在运行时words[0]会产生您的subscript out of range错误。
You should check the size of the vector before accessing it.
您应该在访问之前检查向量的大小。
Try this:
尝试这个：
for(vector<string>::const_iterator it=words.begin(), end=words.end(); it!=end; ++it){
cout << *it << ' ';
}
回答by user640121
Can you please attach the version of the code where you actually push_back strings on the vector. Its not possible to debug the issue unless the code on which reproduce is available for review.
你能附上代码的版本吗，你实际上在向量上推回字符串。除非重现的代码可供，否则无法调试问题。
