View Compilation Error

0_0_21633587_13362.cpp: In function 'int findWordsInTitle(char*, int, int, int)':
0_0_21633587_13362.cpp:62:39: error: 'strcpy' was not declared in this scope
     strcpy(art[num].words[k++], tmpstr);
                                       ^
0_0_21633587_13362.cpp:66:41: error: 'strcpy' was not declared in this scope
     strcpy(queryWords.words[k++] ,tmpstr);
                                         ^
0_0_21633587_13362.cpp: In function 'int compareTwoTitles(Node, Node)':
0_0_21633587_13362.cpp:95:45: error: 'strcmp' was not declared in this scope
    if (!strcmp(word.words[i], title.words[j]))
                                             ^
0_0_21633587_13362.cpp: In function 'int main()':
0_0_21633587_13362.cpp:125:30: error: 'memset' was not declared in this scope
   memset(&art, 0, sizeof(art));
                              ^
0_0_21633587_13362.cpp:132:28: error: 'strlen' was not declared in this scope
    n = strlen(art[i].oldStr);
                            ^