View Compilation Error

0_0_32907815_13786.cpp: In function 'int main()':
0_0_32907815_13786.cpp:11:34: error: 'memset' was not declared in this scope
         memset(sum,0, sizeof sum );
                                  ^
0_0_32907815_13786.cpp:15:36: error: 'strcmp' was not declared in this scope
                 if(strcmp(a[i],a[j])==0){
                                    ^