Compilare: user.cpp: In function ‘void suma(char*)’: user.cpp:16:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<strlen(s)) ^ user.cpp:23:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i<strlen(s)) ^ user.cpp: In function ‘void produse(char*)’: user.cpp:41:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<strlen(s); ++i) ^ user.cpp:55:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<strlen(s); ++i) ^