foo.cc: In function 'void Initialize(int)':
foo.cc:21:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   21 |         for (int i = 0; i < s[id].size(); i++)
      |                         ~~^~~~~~~~~~~~~~
foo.cc:22:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   22 |                 while (i < s[id].size() && (s[id][i] < '0' || s[id][i] > '9') && s[id][i] != '+' && s[id][i] != '-' && s[id][i] != '*' && s[id][i] != '^' && s[id][i] != 'a' && s[id][i] != '(' && s[id][i] != ')')
      |                        ~~^~~~~~~~~~~~~~
foo.cc: In function 'int getPri(char)':
foo.cc:19:1: warning: control reaches end of non-void function [-Wreturn-type]
   19 | }
      | ^

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