stl:set:empty

C++ Reference

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empty

Syntax:

    #include <set>
    bool empty() const;

The empty() function returns true if the set has no elements, false otherwise.

For example, the following code uses empty() to determine if a set is empty:

     // Create a set of characters
     set<char> charSet;
     cout << (charSet.empty() ? "EMPTY " : "NON-EMPTY ");
     charSet.insert( 'A' );
     charSet.insert( 'B' );
     charSet.insert( 'C' );
     cout << (charSet.empty() ? "EMPTY " : "NON-EMPTY ");
     charSet.clear();
     cout << (charSet.empty() ? "EMPTY " : "NON-EMPTY ");
     // output is "EMPTY NON-EMPTY EMPTY "