scanf读取数据后，用for循环打印不出结果?

#include
int main(void)
{
int i;
int uplimit,downlimit;
printf("please enter the uplimit and downlimit of positive integer: \n");
scanf("%d %d",&uplimit,&downlimit);
for (i=downlimit;i<=uplimit;i++)
printf("%5d%5d%5d \n",i,i*i,i*i*i);
return 0;
}