View Compilation Error

0_0_32867844_6887.cpp:1:14: error: expected constructor, destructor, or type conversion before '(' token
         scanf("%s",a);
              ^
0_0_32867844_6887.cpp:2:22: error: 'a' was not declared in this scope
         int n=strlen(a);
                      ^
0_0_32867844_6887.cpp:2:23: error: 'strlen' was not declared in this scope
         int n=strlen(a);
                       ^
0_0_32867844_6887.cpp:5:9: error: expected unqualified-id before 'for'
         for(int i=0;i<n;i++)
         ^
0_0_32867844_6887.cpp:5:21: error: 'i' does not name a type
         for(int i=0;i<n;i++)
                     ^
0_0_32867844_6887.cpp:5:25: error: 'i' does not name a type
         for(int i=0;i<n;i++)
                         ^