foo.cc: In function 'int main()':
foo.cc:10:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  for( c=1;c<=y;c++);
  ^~~
foo.cc:11:2: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
  {
  ^
foo.cc:17:11: warning: comparison of constant '100' with boolean expression is always true [-Wbool-compare]
   if(10<=d<100 && d%11==0)
      ~~~~~^~~~
foo.cc:17:8: warning: comparisons like 'X<=Y<=Z' do not have their mathematical meaning [-Wparentheses]
   if(10<=d<100 && d%11==0)
      ~~^~~
foo.cc:22:12: warning: comparison of constant '1000' with boolean expression is always true [-Wbool-compare]
   if(100<=d<1000 && d%10==(d-d%100)/100)
      ~~~~~~^~~~~
foo.cc:22:9: warning: comparisons like 'X<=Y<=Z' do not have their mathematical meaning [-Wparentheses]
   if(100<=d<1000 && d%10==(d-d%100)/100)
      ~~~^~~
foo.cc:5:6: warning: variable 'n' set but not used [-Wunused-but-set-variable]
  int n,y,z;
      ^