/in/foo.c: In function 'main':
/in/foo.c:13:10: error: expected expression before ',' token
  for(i=0;,i<n-1;i++)
          ^
/in/foo.c:13:10: warning: left-hand operand of comma expression has no effect [-Wunused-value]
/in/foo.c:33:10: error: expected expression before ',' token
  for(i=0;,i<n-1;i++)
          ^
/in/foo.c:33:10: warning: left-hand operand of comma expression has no effect [-Wunused-value]