学用 ASP.Net 之 System.Collections.BitArray 类

常用成员:

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/* 属性 */
Count    //只读
Length   //同 Count, 但可读写

/* 方法 */
And()    //与
Get()    //取值
Not()    //取反
Or()     //或
Set()    //赋值
SetAll() //全部设定为指定值
Xor()    //异或

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练习:

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//(items)[]、Get()、Set()
protected void Button1_Click(object sender, EventArgs e)
{
    BitArray bits = new BitArray(new bool[3] { true, false, true });

    bool b1 = bits[0];       //True
    bool b2 = bits[1];       //False
    //bool b1 = bits.Get(0);
    //bool b2 = bits.Get(1);
    
    bits[0] = false;
    bits[1] = true;
    //bits.Set(0, false);
    //bits.Set(1, true);

    bool b11 = bits[0]; //False
    bool b22 = bits[1]; //True

    TextBox1.Text = string.Concat(b1, "\n", b2, "\n", b11, "\n", b22);
} 

//SetAll() 及遍历
protected void Button2_Click(object sender, EventArgs e)
{
    BitArray bits = new BitArray(5);

    string str1 = "";
    foreach (bool b in bits)
    {
        str1 += b.ToString() + " "; //False False False False False 
    }

    bits.SetAll(true);
    string str2 = "";
    foreach (bool b in bits)
    {
        str2 += b.ToString() + " "; //True True True True True 
    }
    TextBox1.Text = str1 + "\n" + str2;
}

//Count、Length
protected void Button3_Click(object sender, EventArgs e)
{
    BitArray bits = new BitArray(5);

    int n1 = bits.Count; //5

    bits.Length = 3;
    int n2 = bits.Count; //3

    TextBox1.Text = string.Concat(n1, "\n", n2);
}

//Not()
protected void Button4_Click(object sender, EventArgs e)
{
    BitArray bits = new BitArray(new bool[4] { true, false, true, false });
    bits.Not();                             // False,True,  False,True
    TextBox1.Text = string.Format("{0},{1},{2},{3}", bits[0], bits[1], bits[2], bits[3]);
}

//And()
protected void Button5_Click(object sender, EventArgs e)
{
    BitArray bits1 = new BitArray(new bool[4] { true, false, true,  false });
    BitArray bits2 = new BitArray(new bool[4] { true, true,  false, false });

    bits1.And(bits2);                        // True, False, False, False
    TextBox1.Text = string.Format("{0},{1},{2},{3}", bits1[0], bits1[1], bits1[2], bits1[3]);
}

//Or()
protected void Button6_Click(object sender, EventArgs e)
{
    BitArray bits1 = new BitArray(new bool[4] { true, false, true,  false });
    BitArray bits2 = new BitArray(new bool[4] { true, true,  false, false });

    bits1.Or(bits2);                        // True,  True,  True,   False
    TextBox1.Text = string.Format("{0},{1},{2},{3}", bits1[0], bits1[1], bits1[2], bits1[3]);
}

//Xor()
protected void Button7_Click(object sender, EventArgs e)
{
    BitArray bits1 = new BitArray(new bool[4] { true, false, true,  false });
    BitArray bits2 = new BitArray(new bool[4] { true, true,  false, false });

    bits1.Xor(bits2);                        // False,True,  True,  False
    TextBox1.Text = string.Format("{0},{1},{2},{3}", bits1[0], bits1[1], bits1[2], bits1[3]);
}

//其它建立方法
protected void Button8_Click(object sender, EventArgs e)
{
    //对象包含 3 个 true
    BitArray bits1 = new BitArray(3, true);

    //以 byte[] 为参数时, 将把其每个 byte 的 8 个位分别映射为一个元素
    BitArray bits2 = new BitArray(new byte[3] { byte.MaxValue, byte.MinValue, byte.MaxValue });

    //以 int[] 为参数时, 将把其每个 int 的 32 个位分别映射为一个元素
    BitArray bits3 = new BitArray(new int[3] { int.MaxValue, int.MinValue, int.MaxValue });

    int n1 = bits1.Length; //3
    int n2 = bits2.Length; //24
    int n3 = bits3.Length; //96

    string s1, s2, s3;
    s1 = s2 = s3 = "";

    foreach (bool b in bits1) { s1 = string.Concat(s1, Convert.ToByte(b)); } //111

    foreach (bool b in bits2) { s2 = string.Concat(s2, Convert.ToByte(b)); } //11111111
                                                                             //00000000
                                                                             //11111111

    foreach (bool b in bits3) { s3 = string.Concat(s3, Convert.ToByte(b)); } //11111111111111111111111111111110
                                                                             //00000000000000000000000000000001
                                                                             //11111111111111111111111111111110
    TextBox1.Text = string.Concat(n1, "\n", n2, "\n", n3, "\n", s1, "\n", s2, "\n", s3);
}

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