View Compilation Error

0_0_19613342_10405.c: In function 'main':
0_0_19613342_10405.c:5:2: error: expected expression before '/' token
  //printf("\n"); 
  ^
0_0_19613342_10405.c:6:2: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
  for(int i=N;i>0;i--)
  ^
0_0_19613342_10405.c:6:2: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code