Compilare: user.cpp: In function ‘int eval(int)’: user.cpp:16:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (s[st]!=')' && st<strlen(s)) ^ user.cpp:80:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (st!=strlen(s)-1 && s[st]!=')') ^ user.cpp:14:9: warning: unused variable ‘dr’ [-Wunused-variable] int dr=0,nr1=0,nr2=0,nr=0,semn=0; ^