prepare (1/3): 
finished

make (2/3): 
g++ -g -Wall -O2 -o p2.o -c p2.cpp 
g++ -g -Wall -O2 -o sortings.o -c sortings.cpp 
sortings.cpp: In function 'void mergesort(int*, int, int)':
sortings.cpp:77:8: warning: statement has no effect [-Wunused-value]
   for(j;j<sizeB;j++){
        ^
sortings.cpp:82:8: warning: statement has no effect [-Wunused-value]
   for(i;i<sizeA;i++){
        ^
g++ -g -Wall -O2 -o selections.o -c selections.cpp 
g++ -g -Wall -O2 -o main p2.o sortings.o selections.o
finished

clean (3/3): 
finished

all task finished, build successfully