foo.cc: In function ‘int main()’:
foo.cc:10:28: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
   10 |                 if(!(c<='z'&&c>='a'||c<='Z'&&c>='A'||c==' '||c=='.'||c==','||c=='!'||c=='?'))break;
      |                      ~~~~~~^~~~~~~~
foo.cc:14:22: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::__cxx11::basic_string<char>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   14 |         for(int i=0;i<=s.size();i++)
      |                     ~^~~~~~~~~~
foo.cc:17:30: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::__cxx11::basic_string<char>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   17 |                 for(int j=i;j<=i+a.size();j++)
      |                             ~^~~~~~~~~~~~