View Compilation Error

0_0_17463238_23952.cpp: In function 'void init(int)':
0_0_17463238_23952.cpp:40:37: error: 'memset' was not declared in this scope
     memset(instack,0,sizeof(instack));  
                                     ^
0_0_17463238_23952.cpp: In function 'int main()':
0_0_17463238_23952.cpp:94:43: error: 'memset' was not declared in this scope
         memset(indegree,0,sizeof(indegree));  
                                           ^