Compilare: user.cpp: In function ‘void adauga(char*)’: user.cpp:23: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void sterge(char*)’: user.cpp:39: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int nr_aparitii(char*)’: user.cpp:50: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int prefix(char*)’: user.cpp:63: warning: comparison between signed and unsigned integer expressions user.cpp:65: warning: comparison between signed and unsigned integer expressions user.cpp:60: warning: unused variable ‘y’ user.cpp: In function ‘int main()’: user.cpp:77: warning: unused variable ‘i’