How to find words around a particular word in a file

Question

I have a big file in my results. I want to look for words around a specific word in this file. For example, if I have a file like this: I am going home they are going school sam is going to lunch

How can I get words before and after "going" and save it in a hash using C++.

He's probably thinking of an unordered_map – Mike Dinescu Mar 12 '13 at 20:13 — Mike Dinescu, Mar 12 '13 at 20:13

Olaf Dietsche · Answer 1 · 2013-03-12T20:37:45.213

2

You can just read the file word by word, always keeping N words as context. You can store the context in a std::deque which allows a rolling context

const int N = 10;
std::deque<std::string> words_before, words_after;
std::string current_word, w;

// prefetch words before and after
for (int i = 0; i < N; ++i) {
    std::cin >> w;
    words_before.push_back(w);
}

std::cin >> current_word;

for (int i = 0; i < N - 1; ++i) {
    std::cin >> w;
    words_after.push_back(w);
}

// now process the words and keep reading
while (std::cin >> w) {
    words_after.push_back(w);
    // save current_word with the words around words_before, words_after
    words_before.pop_front();
    words_before.push_back(current_word);
    current_word = words_after.front();
    words_after.pop_front();
}

edited Mar 12 '13 at 20:37

answered Mar 12 '13 at 20:14

Olaf Dietsche

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This is a good answer, but technically this wouldn't work for his question. Since there is more than one word between the two 'going's – Memento Mori Mar 12 '13 at 20:16
I have to extract the context of plus/minus 10 words around a particular word – Mar 12 '13 at 20:21
@MementoMori Your comment is reasonable. I updated my answer. – Olaf Dietsche Mar 12 '13 at 20:25
@user2162685 Then I misunderstood your question and this approach won't work for you. – Olaf Dietsche Mar 12 '13 at 20:27
@user2162685 I updated my answer. This is now more wordy, but I hope, you get the idea. – Olaf Dietsche Mar 12 '13 at 20:41
@OlafDietsche Thank you for your answer. I got an idea. I will try to implement this. – Mar 12 '13 at 22:14

How to find words around a particular word in a file

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