机试复习*

通过一些例子重拾一些记不清了的c、c++知识。

首先是位运算：

 

 

 

 

 

然后是一些其他语法、输入输出：

//N诺一天重拾C语言 WebSite: https://noobdream.com//Major/majorinfo/1/

//目录:
	 //1：枚举类型+switch语句
	 //2：枚举类型
	 //3：位运算（原码、反码、补码）
	 //4：bool变量、逻辑运算  ×
	 //5：字符串
	 
	 //6：结构体与链表
	 //7：qsort排序与rand随机技巧
	 
//参考
     //https://learn.microsoft.com/zh-cn/cpp/c-language/c-bitwise-operators?view=msvc-170
     //https://blog.youkuaiyun.com/weixin_45728409/article/details/124492521
     //

//负数的补码，是能够和其相反数相加通过溢出从而使计算机内计算结果变为0的二进制码。

#include <iostream>
#include <stdio.h>
#include <string>

using namespace std;

int main(){
	
	//switch与枚举类型
    enum Day{
    	Mon =1,
		Tue,
		Wed,
		Thur,
		Fri,
		Sat,
		Sun
    };
	enum Day d = Mon;
	
	cout<<d<<endl;
	cout<<"请输入星期:"<<endl;
	//scanf("%u",&d);
    cin>>(int&)d;
    
	switch(d){
		case Mon:
			 cout<<"星期一.."<<endl;
			 break;
		
		case Tue:
			 cout<<"星期二.."<<endl;
			break;
			
		case Wed:
			 cout<<"星期三.."<<endl;
			break;
			
		case Thur:
			 cout<<"星期四.."<<endl;
			break;
			
		case Fri:
			 cout<<"星期五.."<<endl;
			break;
			
		case Sat:
			 cout<<"星期六.."<<endl;
			break;

		case Sun:
		     cout<<"星期天.."<<endl;
			 break;
			 
		default:
			cout<<"耶稣没预料到这天.."<<endl;
			break;
			
	};
	
	
	//位运算：按位取反~、按位与&、按位或|、按位异或^，左移<<、右移>>
	int num1,num2;
	num1 = 1;//原码：0001，补码:0001(负数补码为反码符号位+1)(反码为原码除符号位外按位取反)
	cout<<num1<<endl;
	
	
	//详细解释见Ref 2
	cout<<~num1<<endl; //补码存储，故不再取反加一：0001->1110 ->1001+1=1010,对原码取反，按补码输出

	num2=0b001;
	
	cout<<~num2<<endl;
	
	int num3 = 0b01110000;   //112;
	int num4 = 0b01110001;  //113;
	
	cout<<num3<<endl;
	cout<<num4<<endl;
	
	cout<<(num3&1)<<endl; //偶数
	cout<<(num4&1)<<endl;
	
	cout<<"AA"<<endl;

	int num5 = 0b00000110;
	cout<<~num5<<endl;
	
	int num7 = -8;
	cout<<(num7^1)<<endl;

	int num8 = 3;
	cout<<(num8 << 1)<<endl;

	int num9 = -5;
	cout<<(num9 >> 1)<<endl;
	
	
	//字符串
	
	char str[]="";
	cin>>str;
	cout<<str<<endl;

	int i=0;
	while(str[i]!='\0'){
		i++;
	}
	cout<<i<<endl;
	
	
	string s;
	cin>>s;
	cout<<s<<endl;
	cout<<s.length()<<endl;
	
	
    return 0;

}

不会吧，不会有人机试爆零吧~ 

参考文献

C 按位运算符 | Microsoft Learn

C语言中按位取反操作符详解_c语言按位取反_LoganYang__的博客-优快云博客