prepare (1/3): 
finished

make (2/3): 
g++ -g -Wall -O2 -o main.o -c main.cpp 
main.cpp: In function 'int main()':
main.cpp:16:13: warning: variable 'startTime' set but not used [-Wunused-but-set-variable]
     clock_t startTime,endTime;
             ^~~~~~~~~
main.cpp:16:23: warning: unused variable 'endTime' [-Wunused-variable]
     clock_t startTime,endTime;
                       ^~~~~~~
main.cpp: In function 'int ChoosePivot(int*, int)':
main.cpp:151:9: warning: unused variable 'k' [-Wunused-variable]
     int k=0;
         ^
main.cpp: In function 'int main()':
main.cpp:44:43: warning: 'result' may be used uninitialized in this function [-Wmaybe-uninitialized]
     cout<<"The order-"<<out<<" item is "<<result<<endl;
                                           ^~~~~~
g++ -g -Wall -O2 -o main main.o
finished

clean (3/3): 
finished

all task finished, build successfully