prepare (1/3): 
finished

make (2/3): 
g++ -g -Wall -O2 -o main.o -c main.cpp 
main.cpp: In function 'int partition1(int*, int, int)':
main.cpp:8:9: warning: unused variable 'p' [-Wunused-variable]
     int p=0;
         ^
main.cpp: In function 'int Rselect(int*, int, int)':
main.cpp:57:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
main.cpp: In function 'int Dselect(int*, int, int)':
main.cpp:219:5: warning: control reaches end of non-void function [-Wreturn-type]
     }
     ^
main.cpp:207:35: warning: 'y' may be used uninitialized in this function [-Wmaybe-uninitialized]
         int j=partition2(a,y,0,n-1);
                                   ^
g++ -g -Wall -O2 -o main main.o
finished

clean (3/3): 
finished

all task finished, build successfully