Compilare: main.cpp: In function 'int eval(std::string)': main.cpp:22:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 22 | for(int i=0; i<s.length(); i++) { | ~^~~~~~~~~~~ main.cpp:33:22: warning: comparison of integer expressions of different signedness: 'int' and 'const size_type' {aka 'const long unsigned int'} [-Wsign-compare] 33 | if(found != string::npos){ | ~~~~~~^~~~~~~~~~~~~~~ main.cpp:44:53: warning: control reaches end of non-void function [-Wreturn-type] 44 | string lhs = trimBraces(s.substr(0, currOpIndex)); | ^