Compilare: main.cpp: In function 'int evaluate(std::string)': main.cpp:39:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 39 | for(i = 0; i < tokens.length(); i++){ | ~~^~~~~~~~~~~~~~~~~ main.cpp:59:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 59 | while(i < tokens.length() && | ~~^~~~~~~~~~~~~~~~~ main.cpp: In function 'int applyOp(int, int, char)': main.cpp:26:1: warning: control reaches end of non-void function [-Wreturn-type] 26 | } | ^