View Compilation Error

0_0_13158549_23168.cpp: In function 'int cmp(const void*, const void*)':
0_0_13158549_23168.cpp:22:52: error: 'strcmp' was not declared in this scope
   return strcmp((*(node *)c).name,(*(node *)d).name);
                                                    ^
0_0_13158549_23168.cpp: In function 'int main()':
0_0_13158549_23168.cpp:51:90: error: 'strcmp' was not declared in this scope
     if (person[j].number==mp[newPer[i].newName]&&(strcmp(person[j].name,newPer[i].newName))<0)
                                                                                          ^