View Compilation Error

0_0_33561323_9647.c: In function 'GPA':
0_0_33561323_9647.c:13:2: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
  for (int i = 0; i < 11; i++) {
  ^
0_0_33561323_9647.c:13:2: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code