/in/foo.cc: In function 'int main()':
/in/foo.cc:8:13: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  if((y%4==0)&&(y%100!=0) || (y%400==0))
     ~~~~~~~~^~~~~~~~~~~~
/in/foo.cc:21:5: warning: this 'else' clause does not guard... [-Wmisleading-indentation]
     else
     ^~~~
/in/foo.cc:22:23: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'else'
     cout << 28 <<endl;break;
                       ^~~~~