View Compilation Error

0_0_17882908_759.cpp: In function 'int main()':
0_0_17882908_759.cpp:7:56: error: 'clock' was not declared in this scope
 #define showtime fprintf(stderr,"time = %.15f\n",clock() / (double)CLOCKS_PER_SEC)
                                                        ^
0_0_17882908_759.cpp:80:5: note: in expansion of macro 'showtime'
     showtime;
     ^
0_0_17882908_759.cpp:7:68: error: 'CLOCKS_PER_SEC' was not declared in this scope
 #define showtime fprintf(stderr,"time = %.15f\n",clock() / (double)CLOCKS_PER_SEC)
                                                                    ^
0_0_17882908_759.cpp:80:5: note: in expansion of macro 'showtime'
     showtime;
     ^