View Compilation Error

0_0_28976501_28611.c: In function 'init':
0_0_28976501_28611.c:8:2: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
  for (int i = 1; i <= n; i++) {
  ^
0_0_28976501_28611.c:8:2: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code
0_0_28976501_28611.c: In function 'join':
0_0_28976501_28611.c:29:3: error: expected expression before '/' token
   //num1[a] += num1[prim[a]];
   ^