View Compilation Error

0_0_31770055_19630.c: In function 'OJ56_4':
0_0_31770055_19630.c:5:5: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
     for(int i = 0 ; i <= n / 3; i++)
     ^
0_0_31770055_19630.c:5:5: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code