Compilare: main.cpp: In function 'bool Eval(std::__cxx11::string)': main.cpp:52:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0; i < s.size(); ++i ) { ~~^~~~~~~~~~ main.cpp: In function 'bool Do()': main.cpp:131:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0; i < s1.size(); ++i ) { ~~^~~~~~~~~~~ main.cpp:139:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0; i < s2.size(); ++i ) { ~~^~~~~~~~~~~ main.cpp: In function 'bool Calc(bool, bool, char)': main.cpp:34:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ main.cpp: In function 'int Priority(char)': main.cpp:46:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ main.cpp: In function 'bool Eval(std::__cxx11::string)': main.cpp:97:1: warning: control reaches end of non-void function [-Wreturn-type] } ^