View Compilation Error

0_0_25674786_15005.cpp: In function 'void init()':
0_0_25674786_15005.cpp:13:26: error: 'memset' was not declared in this scope
     memset(a, 0, sizeof a);
                          ^
0_0_25674786_15005.cpp: In function 'int main()':
0_0_25674786_15005.cpp:36:34: error: 'memset' was not declared in this scope
         memset(num, 0, sizeof num);
                                  ^