View Compilation Error

0_0_24653547_10733.c: In function 'prodp':
0_0_24653547_10733.c:14:2: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
  for (int i = n - 2; i >= 0; i--)
  ^
0_0_24653547_10733.c:14:2: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code
0_0_24653547_10733.c:16:3: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
   for (int j = 0; j < r; j++)
   ^
0_0_24653547_10733.c:30:11: error: redefinition of 'i'
  for (int i = 0; i < r; i++)
           ^
0_0_24653547_10733.c:14:11: note: previous definition of 'i' was here
  for (int i = n - 2; i >= 0; i--)
           ^
0_0_24653547_10733.c:30:2: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
  for (int i = 0; i < r; i++)
  ^