View Compilation Error

0_0_18333793_3219.cpp: In function 'int main()':
0_0_18333793_3219.cpp:5:3: error: 'doubler' was not declared in this scope
   doubler,v;
   ^
0_0_18333793_3219.cpp:5:11: error: 'v' was not declared in this scope
   doubler,v;
           ^
0_0_18333793_3219.cpp:6:21: error: 'r' was not declared in this scope
  while(scanf("%lf",&r)!=EOF)
                     ^