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POUnderstanding this bitset implementation (C++)
 

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  1. POUnderstanding this bitset implementation (C++)
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    <p>I just got this frame for a sudoku solver, but I don't understand the syntax they've used and how I'm supposed to proceed. They call it a bitset, but upon searching for it I found nothing similar. </p> <pre><code> // This file contains a simple implementation of sets of // digits between 1 and 9, called fields. #ifndef __SUDOKU_FIELD_H__ #define __SUDOKU_FIELD_H__ #include &lt;iostream&gt; #include &lt;cassert&gt; #include "digit.h" class Field { private: // Use integers for a bitset unsigned int _digits; // Number of digits in bitset unsigned int _size; public: // Initialize with all digits between 1 and 9 included Field(void) : _digits((1 &lt;&lt; 1) | (1 &lt;&lt; 2) | (1 &lt;&lt; 3) | (1 &lt;&lt; 4) | (1 &lt;&lt; 5) | (1 &lt;&lt; 6) | (1 &lt;&lt; 7) | (1 &lt;&lt; 8) | (1 &lt;&lt; 9)), _size(9) {} // Return size of digit set (number of digits in set) unsigned int size(void) const { // FILL IN } // Test whether digit set is empty bool empty(void) const { // FILL IN } // Test whether set is assigned (that is, single digit left) bool assigned(void) const { // FILL IN } // Test whether digit d is included in set bool in(digit d) const { assert((d &gt;= 1) &amp;&amp; (d &lt;= 9)); // FILL IN } // Return digit to which the set is assigned digit value(void) const { assert(assigned()); // FILL IN } // Print digits still included void print(std::ostream&amp; os) const; // Remove digit d from set (d must be still included) void prune(digit d) { assert(in(d)); // FILL IN } // Assign field to digit d (d must be still included) void assign(digit d) { assert(in(d)); // FILL IN } }; // Print field inline std::ostream&amp; operator&lt;&lt;(std::ostream&amp; os, const Field&amp; f) { f.print(os); return os; } #endif </code></pre> <p>Obviously the //FILL IN's are for me to write, and the meaning of the bitset is 9 bits where all of them initially are set to 1. The question is how I manipulate or use them.</p> <p>Oh, by the way, this is a digit:</p> <pre><code>#ifndef __SUDOKU_DIGIT_H__ #define __SUDOKU_DIGIT_H__ typedef unsigned char digit; #endif </code></pre>
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    1. COgoogle, 1st result: http://www.cplusplus.com/reference/stl/bitset/
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    2. CO@OrenS not the same thing.
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    3. CO@OrenS. He need to develop his "own" bitset. Your comment is not helpful.
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