View Compilation Error

0_0_25159839_7587.c: In function 'isprimer':
0_0_25159839_7587.c:8:2: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
  for(int i=2; i<=sqrt(x); i++){
  ^
0_0_25159839_7587.c:8:2: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code
0_0_25159839_7587.c: In function 'main':
0_0_25159839_7587.c:19:2: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
  for(int i=0; i<n; i++){
  ^
0_0_25159839_7587.c:24:4: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
    for(int j = 2; j<=data; j++){
    ^