View Compilation Error

0_0_18301579_20949.c: In function 'prime':
0_0_18301579_20949.c:4:2: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
  for(int i=2;i<=sqrt(x);i++)
  ^
0_0_18301579_20949.c:4:2: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code
0_0_18301579_20949.c: In function 'main':
0_0_18301579_20949.c:12:3: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
   for(int i=x;i<=y;i++)
   ^