View Compilation Error

In file included from 0_0_36870239_3449.cpp:1:0:
0_0_36870239_3449.cpp: In function 'int main()':
0_0_36870239_3449.cpp:6:42: error: ISO C++ forbids comparison between pointer and integer [-fpermissive]
  while(scanf("%f%f%f%f",&x1,&x2,&y1,&y2!=EOF))
                                          ^