View Compilation Error

0_0_20214302_3301.cpp: In function 'bool cmp(const Data&, const Data&)':
0_0_20214302_3301.cpp:7:35: error: 'strcmp' was not declared in this scope
     else return strcmp(d1.ID,d2.ID)<0?1:0;  
                                   ^
0_0_20214302_3301.cpp: In function 'int main()':
0_0_20214302_3301.cpp:15:32: error: 'memset' was not declared in this scope
         memset(d,NULL,sizeof(d));  
                                ^