Compilare: user.cpp: In function 'void buildtree(int)': user.cpp:92: warning: comparison between signed and unsigned integer expressions user.cpp:96: warning: comparison between signed and unsigned integer expressions user.cpp:103: warning: comparison between signed and unsigned integer expressions user.cpp:104: warning: comparison between signed and unsigned integer expressions user.cpp:174: warning: comparison between signed and unsigned integer expressions user.cpp:175: warning: comparison between signed and unsigned integer expressions user.cpp:176: warning: comparison between signed and unsigned integer expressions user.cpp:194: warning: comparison between signed and unsigned integer expressions user.cpp:206: warning: comparison between signed and unsigned integer expressions user.cpp:216: warning: comparison between signed and unsigned integer expressions user.cpp:228: warning: comparison between signed and unsigned integer expressions user.cpp:239: warning: comparison between signed and unsigned integer expressions user.cpp:247: warning: comparison between signed and unsigned integer expressions user.cpp:255: warning: comparison between signed and unsigned integer expressions user.cpp:257: warning: comparison between signed and unsigned integer expressions