問題1：由鍵盤輸入x，y兩個數，要求從小到大排序並輸出

#include <stdio.h>  
int main()  
{  
	float x, y, t;
	scanf("%f%f", &x, &y);
	if (x < y)
	{
		t = x;
		x = y;
		y = t;
	}
	printf("%6.2f, %6.2f", x, y);//佔6列，有2位小數，左端補空格。小數點也佔一列
	return 0;  
}  

問題2：輸入3個整數，按由小到大的順序輸出

#include <stdio.h>  

int main()  
{  
	int a, b, c, t;
	printf("input three integer a,b,c:");
	scanf("%d%d%d",&a,&b,&c);
	if (a > b)
	{
		t = a;
		a = b;
		b = t;
	}

	if (a > c)
	{
		t = a;
		a = c;
		c = t;
	}

	if (b > c)
	{
		t = b;
		b = c;
		c = t;
	}

	printf("now the order is:%d, %d, %d\n", a, b, c);
	return 0;  
}