View Compilation Error

0_0_33900324_3499.cpp:4:10: error: expected constructor, destructor, or type conversion before '(' token
     scanf("%d",&n);
          ^
0_0_33900324_3499.cpp:5:5: error: 'w' does not name a type
     w=n;
     ^
0_0_33900324_3499.cpp:6:5: error: expected unqualified-id before 'while'
     while(n--)
     ^