View Compilation Error

0_0_22251582_29208.cpp: In function 'int main()':
0_0_22251582_29208.cpp:21:31: error: ISO C++ forbids applying 'sizeof' to an expression of function type [-fpermissive]
      memset(prev,0,sizeof(prev));
                               ^
0_0_22251582_29208.cpp:21:32: error: cannot resolve overloaded function 'prev' based on conversion to type 'void*'
      memset(prev,0,sizeof(prev));
                                ^