Compilare: user.cpp: In function ‘int find(long int)’: user.cpp:19: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void erase(long int)’: user.cpp:38: warning: comparison between signed and unsigned integer expressions user.cpp:46: warning: name lookup of ‘i’ changed user.cpp:13: warning: matches this ‘i’ under ISO standard rules user.cpp:38: warning: matches this ‘i’ under old rules