View Compilation Error

0_0_31867659_23073.c: In function 'main':
0_0_31867659_23073.c:6:45: error: expected ')' before '{' token
 while(scanf("%lf%lf%lf%lf",&x,&y,&a,&b!=EOF){
                                             ^
0_0_31867659_23073.c:10:1: error: expected expression before '}' token
 }
 ^