View Compilation Error

0_0_36071774_17303.cpp: In constructor 'juzhen::juzhen()':
0_0_36071774_17303.cpp:12:28: error: 'memset' was not declared in this scope
         memset(a,0,sizeof a);
                            ^
0_0_36071774_17303.cpp: In member function 'void juzhen::build()':
0_0_36071774_17303.cpp:15:28: error: 'memset' was not declared in this scope
         memset(a,0,sizeof a);
                            ^