Compilare: user.cpp: In function ‘void elim_space(char*)’: user.cpp:17:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<strlen(expr);i++) ^ user.cpp: In function ‘void negativ(char*)’: user.cpp:46:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<strlen(expr)-1;i++) ^ user.cpp: In function ‘void forma_pol(char*, char*)’: user.cpp:67:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<strlen(expr);++i) ^ user.cpp: In function ‘long double operatie(long double, long double, char)’: user.cpp:146:1: warning: control reaches end of non-void function [-Wreturn-type] } ^