#include <stdio.h>
#include <conio.h>
/*
sap xep 4 so tang dan

interchange sort
so sanh tung cap so
a - b
a - c
a - d
b - c
b - d
c - d

a => b => c => d
*/

void nhapdulien( int &x)
{
	printf("\nNHAP SO : ");
	scanf("%d",&x);
}
void hoanvicach1 (int &a , int &b)
{
       int temp = a;
	   a = b;
	   b = temp;

}
void hoanvicach2 (int &a, int &b)
{
	  a = a + b; // gan cho a la a + b nen day la ab 
	  b = a - b; // muon b = a thi tren a da la ab thi nen tru di b nen b = a
	  a = a - b;// muon a = b thi tren a da la ab thi nen tru di a nen b = a
}
void sapxepsotangdan (int &a , int &b , int &c, int &d)
{
	        if(a > b)
			{
			   hoanvicach1(a,b);
			}
			if ( a > c)
			{
			     hoanvicach1(a,c);
			}
			if(a > d)
			{
			   hoanvicach1(a,d);
			}
			if(b > c)
			{
			   hoanvicach1(b,c);
			}
			if(b > d)
			{
			   hoanvicach1(b,d);
			}
			if(c > d)
			{
			   hoanvicach1 (c,d);
			}

}
int main()
{     
	 int a, b,c,d;
	 nhapdulien(a);
	 nhapdulien(b);
	 nhapdulien(c);
	 nhapdulien(d);

	 printf("\ntruoc khi tang dan %d => %d => %d => %d",a,b,c,d);
	 //hoanvicach1(a,b);//
	 //hoanvicach2(a,b);//
	 sapxepsotangdan(a,b,c,d);

	 printf("\nSau khi tang dan %d => %d => %d => %d",a,b,c,d);

	getch();
	return 0;



}