View Compilation Error

0_0_13572476_1560.cpp: In function 'int main()':
0_0_13572476_1560.cpp:18:8: error: 'dp' was not declared in this scope
   clr( dp, 0 );
        ^
0_0_13572476_1560.cpp:8:29: note: in definition of macro 'clr'
 #define clr( a, b ) memset( a, b, sizeof(a) )
                             ^