View Compilation Error

0_0_36487009_25313.cpp: In function 'int main()':
0_0_36487009_25313.cpp:74:37: error: 'memset' was not declared in this scope
         memset(tree, 0, sizeof(tree));
                                     ^
0_0_36487009_25313.cpp:81:34: error: 'strcmp' was not declared in this scope
             if (strcmp(temp, "in") == 0)
                                  ^
0_0_36487009_25313.cpp:96:24: error: 'sort' was not declared in this scope
         sort(b, b + cnt);
                        ^