View Compilation Error

0_0_19790217_23114.cpp: In function 'int main()':
0_0_19790217_23114.cpp:4:24: error: 'n' was not declared in this scope
     while(scanf("%lf",&n)!=EOF) 
                        ^
0_0_19790217_23114.cpp:11:23: error: 'n' was not declared in this scope
      printf("%.2lf\n",n);
                       ^