/in/foo.cc: In function 'int main()':
/in/foo.cc:19:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   19 |         for (int i = 0; i <= s1.length() - 1; i++){
      |                         ~~^~~~~~~~~~~~~~~~~~
/in/foo.cc:24:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   24 |         for (int i = 0; i <= s3.length() - 1; i++)
      |                         ~~^~~~~~~~~~~~~~~~~~
/in/foo.cc:27:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   27 |         for (int i = 1; i <= s1.length(); i++) {
      |                         ~~^~~~~~~~~~~~~~
/in/foo.cc:28:44: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   28 |                 if (bch1[ch1[i]] != ch2[i] && bl1[ch1[i]] != 0 || bch2[ch2[i]] != ch1[i] && bl2[ch2[i]] != 0) {
      |                     ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~
/in/foo.cc:45:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   45 |         for (int i = 1; i <= s3.length(); i++) {
      |                         ~~^~~~~~~~~~~~~~