View Compilation Error

0_0_28098444_14359.c: In function 'makeNext':
0_0_28098444_14359.c:10:2: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
  for (int i = 1, k = 0; i < len; i++)
  ^
0_0_28098444_14359.c:10:2: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code
0_0_28098444_14359.c: In function 'main':
0_0_28098444_14359.c:31:3: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
   for (int i = 0; i < temp; i++)
   ^