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    <p><code>std::string</code> already includes a working overload of <code>operator&lt;</code>, so you can just compare strings directly. Java uses <code>compareTo</code> primarily because the built-in comparison operator produces results that aren't generally useful for strings. Being a lower-level language, Java doesn't support user-defined operator overloads, so it uses <code>compareTo</code> as a band-aid to cover for the inadequacy of the language.</p> <p>From your description, however, you don't need to deal with <em>any</em> of that directly at all. At least as you've described the problem, you really want is something like:</p> <pre><code>std::map&lt;std::string, std::vector&lt;int&gt; &gt; page_map; </code></pre> <p>You'll then read words in from your text file, and insert the page number where each occurs into the page map:</p> <pre><code>page_map[current_word].push_back(current_page); </code></pre> <p>Note that I've used <code>std::map</code> above, on the expectation that you may want ordered results (e.g., be able to quickly find all words from <code>age</code> to <code>ale</code> in alphabetical order). If you don't care about ordering, you may want to use <code>std::unordered_map</code> instead.</p> <p>Edit: here's a simple text cross-reference program that reads a text file (from standard input) and writes out a cross-reference by line number (i.e., each "word", and the numbers of the lines on which that word appeared).</p> <pre><code>#include &lt;map&gt; #include &lt;unordered_map&gt; #include &lt;iostream&gt; #include &lt;string&gt; #include &lt;vector&gt; #include &lt;sstream&gt; #include &lt;iterator&gt; #include "infix_iterator.h" typedef std::map&lt;std::string, std::vector&lt;unsigned&gt; &gt; index; namespace std { ostream &amp;operator&lt;&lt;(ostream &amp;os, index::value_type const &amp;i) { os &lt;&lt; i.first &lt;&lt; ":\t"; std::copy(i.second.begin(), i.second.end(), infix_ostream_iterator&lt;unsigned&gt;(os, ", ")); return os; } } void add_words(std::string const &amp;line, size_t num, index &amp;i) { std::istringstream is(line); std::string temp; while (is &gt;&gt; temp) i[temp].push_back(num); } int main() { index i; std::string line; size_t line_number = 0; while (std::getline(std::cin, line)) add_words(line, ++line_number, i); std::copy(i.begin(), i.end(), std::ostream_iterator&lt;index::value_type&gt;(std::cout, "\n")); return 0; } </code></pre> <p>If you look at the first <code>typedef</code> (of <code>index</code>), you can change it from <code>map</code> to <code>unordered_map</code> if you want to test a hash table vs. a red-black tree. Note that this interprets "word" pretty loosely -- basically any sequence of non-whitespace characters, so for example, it'll treat <code>example,</code> as a "word" (and it'll be separate from <code>example</code>).</p> <p>Note that this uses the <code>infix_iterator</code> I've posted <a href="https://codereview.stackexchange.com/q/13176/489">elsewhere</a>.</p>
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    1. POIs there a CompareTo method in C++ similar to Java where you can use > < = operations on a data type
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    1. USJerry Coffin
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    1. COThis actually makes a lot of sense to me instead of creating a whole class which maps a vector to the string that way. So in that case i would be adding maps (of strings and vectors) to a tree or hashtable (which is what i want to do) than when i do a find operations (in this case i have it defined to return the data) it will return a map. From which i can access the pages. However when doing comparisons in a tree will the map compare the strings or the vector? Pretty much all i need to be doing in this exercise is to store words with an index of page numbers it occurs on using different trees
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      1. USuser2665682
    2. COWhy would you add the map to a tree or hashtable? The map *is* a tree (and unordered_map is a hash table). It already takes you directly from word to page number(s).
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    3. COI have already constructed a redblacktree, binarytree, hashtable, chainedhashtable and a few more data structures. All of these have their own adds,removes, and finds that take a paramete T x so it can be used in any case. Thats why i though creating my own data type which stores a string and an array was the best option, i dont know how to compare though. The idea is to index the words using each of these data structures (So i can change in between then than observe the running times of each data structure) and add an array ossociated with the word that stores the page numbers it occures on.
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