/in/foo.cc: In function 'void fft(cp*, int, int)':
/in/foo.cc:20:3: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
   for(k=(n>>1);k&i;i^=k,k>>=1);i^=k;
   ^~~
/in/foo.cc:20:32: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for'
   for(k=(n>>1);k&i;i^=k,k>>=1);i^=k;
                                ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:40:50: warning: narrowing conversion of '(((int)ch[i]) - 48)' from 'int' to 'long double' inside { } [-Wnarrowing]
  for(int i=len1-1;i>=0;i--)a[len1-i-1]=(cp){ch[i]-'0',0};
                                             ~~~~~^~~~
/in/foo.cc:43:50: warning: narrowing conversion of '(((int)ch[i]) - 48)' from 'int' to 'long double' inside { } [-Wnarrowing]
  for(int i=len2-1;i>=0;i--)b[len2-i-1]=(cp){ch[i]-'0',0};
                                             ~~~~~^~~~