#include <stdio.h>

void line_up(double *ap,double *bp)
{
	double temp;
	temp=*ap;
	*ap=*bp;
	*bp=temp;
}
int main()
{
	double a, b;

	printf("¼ýÀÚ µÎ °³¸¦ ÀÔ·ÂÇϼ¼¿ä : ");
	scanf("%lf%lf",&a,&b);

	printf("¹Ù²Ù±â ÀüÀÇ a, bÀÇ °ª : %lf, %lf\n",a,b);

	line_up(&a,&b);
	printf("¹Ù²Û ÈÄÀÇ a, bÀÇ °ª : %lf, %lf\n",a,b);

	return 0;
}