[C++知识库]C++学习第三天笔记

1.逻辑运算符

#include <iostream>
using namespace std;


int main()
{
	int a = 10;
	
	cout << !a << endl;
	cout << !!a << endl;	//这也是一种简单的非零数字转换成1的方法
	cout << (a && b) << endl;	//不打括号报错
	cout << (a || b) << endl;	//不打括号报错

	system("pause");
	return 0;
}

2.选择语句

#include <iostream>
using namespace std;


int main()
{
	while (1)
	{
		int score;
		cout << "请输入一个分数" << endl;
		cin >> score;
		cout << "你输入的分数是" << score << endl;
		if (100<score && score<150)	//不能写为if(100<score<150);这样设置条件不合规
		{
			cout << "恭喜你考试重本" << endl;

		}
		else if(150<score && score<200)
		{
			cout << "成功被清华录取" << endl;

		}
		else if (score > 200)
		{
			cout << "你狗日的作弊被捕" << endl;
		}
		else
		{
			cout << "很遗憾你没考上重本" << endl;
		}
	}
	
	system("pause");
	return 0;
}

3.switch语句

#include <iostream>
using namespace std;

int main()
{
	int score = 0;
	cout << "请给电影打个合适的分数" << endl;
	cin >> score;
	cout << "你打的分数是" << score << endl;

	switch (score)	//只能是整形或字符型
	{
	case 10: cout << "经典电影" << endl;
		break;
	case 9: cout << "非常好看" << endl;
		break;
	case 8: cout << "好看" << endl;
		break;
	default:cout << "一般" << endl;
		break;
	}

	system("pause");
	return 0;
}