View Compilation Error

0_0_18373079_14551.cpp: In function 'void f(int, int, int)':
0_0_18373079_14551.cpp:20:23: error: return-statement with a value, in function returning 'void' [-fpermissive]
  if(n==1||n==2)return 1;
                       ^
0_0_18373079_14551.cpp:23:17: error: invalid operands of types 'int' and 'void' to binary 'operator*'
   s=(A*f(A,B,n-1)+B*f(A,B,n-2))%7;
                 ^
0_0_18373079_14551.cpp:23:30: error: invalid operands of types 'int' and 'void' to binary 'operator*'
   s=(A*f(A,B,n-1)+B*f(A,B,n-2))%7;
                              ^