/in/foo.cc: In member function 'void ComplexArray::BubbleSort()':
/in/foo.cc:78:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < a.size() - 1; i++)
                   ~~^~~~~~~~~~~~~~
/in/foo.cc:79:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for (int j = 0; j < a.size() - i - 1; j++)
                    ~~^~~~~~~~~~~~~~~~~~
/in/foo.cc: In member function 'void ComplexArray::Output()':
/in/foo.cc:86:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < a.size(); i++)
                   ~~^~~~~~~~~~