C# 入門指南 - encrypt.cs




encrypt.cs 的程式原始碼如下

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using System;
using System.Text;
 
namespace Encryptor {
    class Encrypt {
        private string cArray;
         
        public string Code {
            get { return cArray; }
            set {
                if (value is string && value.Length == 26) {
                    cArray = value;
                }
                else {
                    Console.WriteLine("something worng!!");
                }
            }
        }
         
        public Encrypt() {
            Random r = new Random();
            int a = 0;
            int b = 0;
            while (a % 2 == 0) {
                a = r.Next(1, 10);
                b = r.Next(1, 10);
                 
            }
              
            int x, y, m;
            char c = 'a';
            int i;
            StringBuilder s = new StringBuilder();
            for (i = 0; i < 26; i++) {
                x = c;
                y = x * a + b;
                m = y % 26;
                s.Append((char) (m + 97));
                c++;
            }
     
            this.cArray = s.ToString();  
        }
         
        public string toEncode(string s) {
            StringBuilder r = new StringBuilder();
             
            // 進行編碼轉換
            char c;
            int i, m;
            for (i = 0; i < s.Length; i++) {
                if (s[i] >= 97 && s[i] <= 122) {
                    c = s[i];
                    m = c - 97;
                    r.Append(this.Code[m]);
                }
                else {
                    r.Append(s[i]);
                }
             }
              
             // 回傳字串
             return r.ToString();
        }
         
        public string toDecode(string s) {
            StringBuilder r = new StringBuilder();
             
            // 進行解碼的工作
            int i, j;
            for (i = 0; i < s.Length; i++) {
                if (s[i] >= 97 && s[i] <= 122) {
                    // 找出表格中對應的索引值
                    for (j = 0; j < 26; j++) {
                        if (s[i] == this.Code[j]) {
                            r.Append((char) (j + 97));
                            break;
                        }
                    }
                }
                else {
                    r.Append(s[i]);
                }
            }
     
            return r.ToString();
        }
    }
}
 
/* 《程式語言教學誌》的範例程式
    http://pydoing.blogspot.com/
    檔名：encrypt.cs
    功能：示範 C# 程式
    作者：張凱慶
    時間：西元 2012 年 10 月 */


您可以繼續參考
範例程式碼


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參考資料
C# 程式設計手冊
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