foo.cc: In function ‘int main()’:
foo.cc:9:22: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::__cxx11::basic_string<char>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
    9 |         for(int i=0;i<=str.length()<1;i++)
      |                     ~^~~~~~~~~~~~~~
foo.cc:9:22: warning: comparisons like ‘X<=Y<=Z’ do not have their mathematical meaning [-Wparentheses]
foo.cc:14:18: warning: format ‘%s’ expects argument of type ‘char*’, but argument 2 has type ‘int’ [-Wformat=]
   14 |         printf("%s",A[n[i]-64]);
      |                 ~^  ~~~~~~~~~~
      |                  |           |
      |                  char*       int
      |                 %d