c use Makefile test

created a Makefile:

build: register_test.c
        gcc -c register_test.c 
link: register_test.o
        gcc -o register_test register_test.o
run: register_test
        ./register_test
clean:
        rm -f *.o *.exe *.executable
ou:
        cd output/
        make -C Makefile





create a .c file:

regitster_test.c (測試用register 有沒有比較省時


#include <stdio.h>
#include <sys/time.h>

int main( int argc, char* argv[])
{
   struct timeval start, end;
   gettimeofday( &start, NULL);
   double timeuse;
   register double sum;
   register int j,k;
   for(j=0;j<1000000000;j++)
        for(k=0;k<10;k++)
            sum=sum+1.0;
   gettimeofday( &end, NULL);
   timeuse  = 1000000*(end.tv_sec - start.tv_sec)+ end.tv_sec-start.tv_usec;
   timeuse /= 1000000;
     printf(" implement time : %f \n", timeuse);


    return 0;
}