View Compilation Error

0_0_19181275_28652.cpp: In function 'int main()':
0_0_19181275_28652.cpp:71:21: error: 'i' was not declared in this scope
         memset(head[i],-1,sizeof(head));
                     ^
0_0_19181275_28652.cpp:71:39: error: 'memset' was not declared in this scope
         memset(head[i],-1,sizeof(head));
                                       ^