View Compilation Error

0_0_23025081_16389.c: In function 'main':
0_0_23025081_16389.c:4:34: error: 'EOF' undeclared (first use in this function)
  while(scanf("%c%c%c",&a,&b,&c)!=EOF)
                                  ^
0_0_23025081_16389.c:4:34: note: each undeclared identifier is reported only once for each function it appears in