Compilare: main.cpp: In function 'int getNextNum(std::string&, int&)': main.cpp:14:67: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 14 | while(expression[pos] >= '0' && expression[pos] <= '9' && pos < expression.size()){ | ~~~~^~~~~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:65:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 65 | while(pos < expression.size()){ | ~~~~^~~~~~~~~~~~~~~~~~~