Question

C#字符串加密

设计一个方法 可以将字符串按下面要求加密:
字符串最后一个字母放在加密后的第一位,其它字母的值偏移3.
主程序负责接收用户键入的字符串,之后调用该方法加密,加密后主程序显示在屏幕上.
例: 明文=“Welcome” 密文=“eZhofrp”

Answer 1

string a = "Welcome";
string b = null;
int num = a.Length;
int ascii;
char ch;
b = a.Substring(a.Length - 1, 1);
for (int i = 0; i < num - 1; i++)
{
ascii = Convert.ToInt32(Convert.ToChar(a.Substring(i, 1)));
ch = Convert.ToChar(ascii + 3);
b += ch;
}
MessageBox.Show("明文="+a +"密文="+b);

Answer 2

private string Encode(string Value)
{
int l = Value.Length;
string OutputString = Value.Substring(l-1,1);
char[] buff=Value.ToCharArray(0,l-1);
for (int i = 0; i < buff.Length; i++)
OutputString += ((char)(buff[i] + 3)).ToString();
return OutputString;
}

Answer 3

StringBuilder str=new StringBuilder("hdkahdkjsahdkas",100);
for(int i=(int)'z';i>=(int)'a';i--)
{char old1=(char)i;
char new1= (char)(i+1);
str = str.Replace(old1,new1);
}
for(int i=(int)'Z';i>=(int)'A';i--)
{char old1=(char)i;
char new1=(char)(i+1);
str = str.Replace(old1,new1);
}
Console.WriteLine(str.ToString());

大概就这样了，偷懒没考虑没考虑吧A—》Z or a—》z