View Compilation Error

0_0_15305424_27296.cpp:3:11: error: '::main' must return 'int'
 void main()
           ^
0_0_15305424_27296.cpp: In function 'int main()':
0_0_15305424_27296.cpp:6:43: error: expression list treated as compound expression in initializer [-fpermissive]
   int scanf("%lf%lf%lf%lf",&x1,&y1,&x2,&y2);
                                           ^
0_0_15305424_27296.cpp:6:43: error: invalid conversion from 'double*' to 'int' [-fpermissive]
0_0_15305424_27296.cpp:7:15: error: 'scanf' cannot be used as a function
   while(scanf()!=EOF)
               ^