Compilare: user.cpp: In function ‘int eval_and(char*)’: user.cpp:44:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(a[p]=='&'&& p<strlen(a)) ^ user.cpp: In function ‘int eval_xor(char*)’: user.cpp:54:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(a[p]=='^'&& p<strlen(a)) ^ user.cpp: In function ‘int eval_or(char*)’: user.cpp:64:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(a[p]=='|' && p<strlen(a)) ^ user.cpp: In function ‘int eval(char*)’: user.cpp:30:12: warning: ‘ans’ may be used uninitialized in this function [-Wmaybe-uninitialized] return ans; ^