View Compilation Error

0_0_19547631_21107.c: In function 'main':
0_0_19547631_21107.c:9:33: error: 'EOF' undeclared (first use in this function)
  while(scanf("%lld%lld",&a,&b)!=EOF)
                                 ^
0_0_19547631_21107.c:9:33: note: each undeclared identifier is reported only once for each function it appears in
0_0_19547631_21107.c:16:2: error: expected expression before '/' token
  // flag=0;
  ^
0_0_19547631_21107.c:18:2: error: expected expression before '/' token
  // printf("c=%d\n",c);
  ^