/in/foo.cc: In function 'int main()':
/in/foo.cc:12:13: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   12 |     while (i< expression.length() && isdigit(expression[i])) {
      |            ~^~~~~~~~~~~~~~~~~~~~~
/in/foo.cc:20:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   20 |     while (i < expression.length()) {
      |            ~~^~~~~~~~~~~~~~~~~~~~~
/in/foo.cc:32:18: warning: 'result' may be used uninitialized [-Wmaybe-uninitialized]
   32 |     std::cout << result << std::endl;
      |                  ^~~~~~
/in/foo.cc:25:9: note: 'result' was declared here
   25 |     int result;
      |         ^~~~~~