去除重复的字符

static public void DeleteRepeatChar(string s){
    Dictionary<char, int> d = new Dictionary<char, int>();
    foreach (var c in s){
        int num = 0;
        if (d.TryGetValue(c, out num)){
            d[c] += 1;
            Console.WriteLine(c);
        }else{
            d[c] = 1;
        }
    }
    string strs = "";
    foreach (var str in d.Keys){
        strs += str;
    }
    Console.WriteLine(strs);
}
static string AcceptmultiLineChars() {
    ConsoleKeyInfo cki;
    Console.TreatControlCAsInput = true;//防止Ctrl+C复制
    Console.WriteLine("Press the CTRL+Enter key to quit: 
");
    string result = string.Empty;
    do {
        cki = Console.ReadKey();
        if (cki.Key == ConsoleKey.Enter) {
            result += System.Environment.NewLine;//如果输入回车，则加入换行标志
            Console.SetCursorPosition(0, Console.CursorTop + 1);//光标下移一行
        }
        result += cki.KeyChar;
    } while (cki.Key != ConsoleKey.Enter || (cki.Modifiers & ConsoleModifiers.Control) == 0);//按Ctrl+Enter退出
    return result;
}
static void Main(string[] args){
    string s = AcceptmultiLineChars();
    DeleteRepeatChar(s);
}

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