C#面试题伪代码

Posted 2021-02-18 z415353144

收集了几个常见的要求写伪代码的面试题:

  1  class Program
  2     {
  3         static void Main(string[] args)
  4         {
  5             Console.WriteLine("Hello World!");
  6             DoBubbleSorting();
  7             Calc(6);
  8             CalcFibonacciSequence(8);
  9             DoIsPower();
 10             TestStringLength();
 11             TestStruct();
 12         }
 13 
 14 
 15         /// <summary>
 16         /// 面试题1、冒泡排序
 17         /// </summary>
 18         public static void DoBubbleSorting()
 19         {
 20             int[] array = {3, 1, 9, 5, 6, 7};
 21             
 22             Console.WriteLine("排序前数字：");
 23             Console.WriteLine(string.Join(",", array));
 24             for (int i = 0; i < array.Length; i++)
 25             {
 26                 for (int j = i + 1; j < array.Length; j++)
 27                 {
 28                     if (array[i] > array[j])
 29                     {
 30                         int tmp = array[j];
 31                         array[j] = array[i];
 32                         array[i] = tmp;
 33                     }
 34                 }
 35             }
 36             Console.WriteLine("排序后数字：");
 37             Console.WriteLine(string.Join(",",array));
 38         }
 39 
 40         /// <summary>
 41         /// 面试题2、求以下表达式的值，写出您想到的一种或几种实现方法：1-2+3-4+……+m
 42         /// </summary>
 43         public static void Calc(int count)
 44         {
 45             Console.WriteLine("求以下表达式的值，写出您想到的一种或几种实现方法：1-2+3-4+……+m");
 46             int num = 0;
 47             for (int i = 1; i <= count; i++)
 48             {
 49                 if (i % 2==1)
 50                 {
 51                     num += i;
 52                 }
 53                 else
 54                 {
 55                     num -= i;
 56                 }
 57             }
 58             Console.WriteLine($"{count}个数值为："+num);
 59         }
 60 
 61         /// <summary>
 62         /// 面试题3、一列数的规则如下: 1、1、2、3、5、8、13、21、34...... 求第30位数是多少，用递归算法实现
 63         /// </summary>
 64         public static void CalcFibonacciSequence(int num) 
 65         {
 66             Console.WriteLine("一列数的规则如下: 1、1、2、3、5、8、13、21、34...... 求第30位数是多少，用递归算法实现");
 67             Console.WriteLine($"第{num}个数是："+Fibonacci(num));
 68         }
 69 
 70         static int Fibonacci(int num)
 71         {
 72             if (num > 0 && num <= 2)
 73             {
 74                 return 1;
 75             }
 76             else
 77             {
 78                 return Fibonacci(num - 1) + Fibonacci(num - 2);
 79             }
 80         }
 81 
 82         public static void DoIsPower()
 83         {
 84             Console.WriteLine("现有一个整数number，请写一个方法判断这个整数是否是2的N次方,以4(100)    7(0111)    8(1000)为例");
 85 
 86             Console.WriteLine("4 & 3 --> 100 & 011     = 0");
 87             Console.WriteLine("7 & 6 --> 0111 & 0110  != 0");
 88             Console.WriteLine("8 & 7 --> 1000 & 0111   = 0");
 89 
 90             Console.WriteLine(GetFlag(5)?"":"5不是2的N次方");
 91             Console.WriteLine(GetFlag(16) ? "16是2的N次方" : "");
 92         }
 93 
 94         public static bool GetFlag(int num)
 95         {
 96             return (num > 0) && (num & num - 1) == 0;
 97         }
 98 
 99         /// <summary>
100         /// 面试题5
101         /// </summary>
102         public static void TestStringLength()
103         {
104             string strTmp = "abcdefg某某某";
105             Console.WriteLine($"{strTmp}的二进制长度和字符串长度各是多少？");
106             Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
107             //int i = System.Text.Encoding.GetEncoding("gb2312").GetBytes(strTmp).Length;
108             int i = System.Text.Encoding.Default.GetBytes(strTmp).Length;//卧槽，这里有坑，默认字符集utf8的话汉字是2-4个字节，这里是16个，gb2312的话，应该是13个吧
109             int j = strTmp.Length;
110             Console.WriteLine($"二进制长度{i},字符串长度{j}");
111         }
112 
113         /// <summary>
114         /// 面试题6
115         /// </summary>
116         public static void TestStruct()
117         {
118             var obj=new MyStruct(100,100);
119             var obj2 = obj;
120             obj2.X = 200;
121             Console.WriteLine($"obj.X->{obj.X},obj.Y->{obj.Y};obj2.X->{obj2.X},obj2.Y->{obj2.Y}");
122         }
123     }
124 
125     /// <summary>
126     /// 面试题4、请写出C#中的单例模式
127     /// </summary>
128     public class Single
129     {
130         private static Single instance;
131         private Single() { }
132         public static Single GetInstance()
133         {
134             if (instance == null)
135             {
136                 instance = new Single();
137             }
138             return instance;
139         }
140     }
141 
142 
143     public struct MyStruct
144     {
145         public MyStruct(int x, int y)
146         {
147             X = x;
148             Y = y;
149         }
150 
151         public int X { get; set; }
152          public int Y { get; set; }
153 
154 
155     }

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