Compilare: main.cpp: In function 'int main()': main.cpp:36:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 36 | for( int i = 0; i < s.size(); ++i ) { | ~~^~~~~~~~~~ main.cpp:40:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 40 | while( i < s.size() && isdigit( s[i] ) ) { | ~~^~~~~~~~~~ main.cpp: In function 'int operatorPriority(char)': main.cpp:21:1: warning: control reaches end of non-void function [-Wreturn-type] 21 | } | ^ main.cpp: In function 'int operate(int, int, char)': main.cpp:28:1: warning: control reaches end of non-void function [-Wreturn-type] 28 | } | ^