View Compilation Error

0_0_16321618_10407.cpp: In function 'int main()':
0_0_16321618_10407.cpp:42:57: error: 'strcmp' was not declared in this scope
                 if(strcmp(first_people.atime, temp.atime)>0)
                                                         ^
0_0_16321618_10407.cpp:45:56: error: 'strcmp' was not declared in this scope
                 if(strcmp(last_people.ltime, temp.ltime)<0)
                                                        ^