View Compilation Error

0_0_21912954_1866.cpp: In function 'bool ishalf()':
0_0_21912954_1866.cpp:25:32: error: 'memset' was not declared in this scope
      memset(flag,0,sizeof(flag));  
                                ^
0_0_21912954_1866.cpp: In function 'int find()':
0_0_21912954_1866.cpp:46:38: error: 'memset' was not declared in this scope
     memset(havever,-1,sizeof(havever));  
                                      ^