prepare (1/3): 
finished

make (2/3): 
g++ -g -Wall -O2 -o main.o -c main.cpp 
g++ -g -Wall -O2 -o sort.o -c sort.cpp 
sort.cpp: In function 'int RSelect(int*, int, int, int)':
sort.cpp:151:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
sort.cpp: In function 'int DSelect(int*, int, int, int)':
sort.cpp:79:2: warning: assuming signed overflow does not occur when assuming that (X + c) < X is always false [-Wstrict-overflow]
  if (left>=right) {
  ^~
g++ -g -Wall -O2 -o main main.o sort.o
finished

clean (3/3): 
finished

all task finished, build successfully