View Compilation Error

0_0_33914444_791.c: In function 'SUM':
0_0_33914444_791.c:5:2: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
  for (int j = 0; j <= n; j++)
  ^
0_0_33914444_791.c:5:2: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code