View Compilation Error

0_0_30284809_23615.cpp: In function 'void lis()':
0_0_30284809_23615.cpp:18:29: error: 'memset' was not declared in this scope
     memset(num,0,sizeof(num));
                             ^
0_0_30284809_23615.cpp: In function 'int main()':
0_0_30284809_23615.cpp:44:33: error: 'memset' was not declared in this scope
         memset(vis,0,sizeof(vis));scanf("%d",&n);
                                 ^