C++Primer:练习1.17 1.18 1.19

练习1.17+1.18

没有重复值（最后要输入文件结束符跳出while循环）

有重复值

练习1.19

#include<iostream>
using namespace std;

int main()
{
    
    
	int val1, val2;

	cout << "Please input two integer:" << endl;
	cin >> val1 >> val2;

	int t;
	if (val1 > val2)
	{
    
    
		t = val1;
		val1 = val2;
		val2 = t;
	}

	while (val1 <= val2)
	{
    
    
		cout << val1 << ' ';
		++val1;
	}
	cout << endl;

	return 0;
}