View Compilation Error

0_0_14300099_18108.cpp: In function 'void init()':
0_0_14300099_18108.cpp:11:33: error: 'memset' was not declared in this scope
     memset(prime,0,sizeof(prime));
                                 ^
0_0_14300099_18108.cpp: In function 'long long int com(int, int)':
0_0_14300099_18108.cpp:48:25: error: 'memset' was not declared in this scope
     memset(a,0,sizeof(a));
                         ^