/in/foo.c: In function 'main':
/in/foo.c:43:33: warning: left-hand operand of comma expression has no effect [-Wunused-value]
  for (i = n1, j = 0; i < n1 + n2, j < n2; i++, j++) {
                                 ^
/in/foo.c:55:33: warning: left-hand operand of comma expression has no effect [-Wunused-value]
  for (i = n1, j = 0; i < n1 + n3, j < n3; i++, j++) {
                                 ^