View Compilation Error

0_0_23725992_17978.cpp: In function 'node poww(node, ll)':
0_0_23725992_17978.cpp:53:39: error: 'memset' was not declared in this scope
     memset(ans1.map,0,sizeof(ans1.map));
                                       ^
0_0_23725992_17978.cpp: In function 'int main()':
0_0_23725992_17978.cpp:78:37: error: 'memset' was not declared in this scope
         memset(x.map,0,sizeof(x.map));
                                     ^