C#实现字符串类

C#实现字符串类。学完之后对数据结构还有C#有了更深层次的理解。有正在学的的朋友，欢迎探讨。QQ：848367854

namespace _stringStudy
{
    class StringDS
    {
        private char[] data;                    //字符串数组用来存放字符

        public StringDS(char[] array)           //构造
        {
            data = new char[array.Length];
            for(int i =0; i < data.Length; i++)
            {
                data[i] = array[i];
            }
        }
        public StringDS(string str)             //构造
        {
            data = new char[str.Length];
            for(int i=0; i<str.Length; i++)
            {
                data[i] = str[i];
            }
        }

        public char this[int index]             //根据索引访问字符的索引器
        {
            get { return data[index]; }
        }

        public int GetLength()                  //取得字符串长度的方法
        {
            return data.Length;
        }
        /// <summary>
        ///  1.如果当前字符串等于s返回0
        ///  2.如果当前字符大于s,返回1
        ///  3.如果当前字符小于s,返回-1
        ///  4.如果当前字符串长度大s的长度，返回1，否则返回-1
        /// </summary>
        /// <param name="s"></param>
        /// <returns></returns>
        public int Compare(StringDS s)
        {
            int index = -1;                                     //索引
            int len = this.GetLength() < s.GetLength() ? this.GetLength() : s.GetLength();//三目运算符，找到长度小的字符串长度
            for (int i = 0; i < len; i++)
            {
                if (this[i] != s[i])                            //只要发现一处字符不同，把该字符索引值赋值给index
                {
                    index = i;
                    break;                                      //一经发现不同，立即跳出循环
                }
            }
            if(index != -1)                                     //字符串前len个长度找到了不同的字符，并记录不同字符处索引值为 index
            {
                if (this[index]> s[index])                     //如果当前字符串第index位置的字符值大于 s字符串第index位置的值，返回1
                {
                    return 1;
                }
                else                                           //如果当前字符串第index位置的字符值小于 s字符串第index位置的值，返回-1
                {
                    return -1;
                }
            }
            else                                                //字符串前len个字符都相同，又分3种情况
            {
                if(this.GetLength() == s.GetLength())          // 情况1：当前字符串串长度等于s字符串长度，返回0
                {
                    return 0;
                }
                else
                {
                    if (this.GetLength() > s.GetLength())      // 情况2: 当前字符串长度大于s字符串，返回 1
                    {
                        return 1;
                    }
                    else                                       // 情况3：当前字符串长度小于s字符串，返回-1
                    {
                        return -1;
                    }
                }


            }
        }
        public StringDS SubString(int index, int length)
        {
            char[] newChar = new char[length];
            for(int i = index; i < index + length; i++)
            {
                newChar[i - index] = data[i];
            }
            return new StringDS(newChar);
        }
        public StringDS Concat(StringDS s1,StringDS s2)
        {
            char[] newChar = new char[s1.GetLength() + s2.GetLength()];
            for(int i = 0; i < s1.GetLength(); i++)
            {
                newChar[i] = s1[i];
            }
            for(int i = s1.GetLength(); i < newChar.Length; i++)
            {
                newChar[i] = s2[i - s1.GetLength()];
            }
            return new StringDS(newChar);
        }
        public int IndexOf(StringDS s)
        {
            for(int i = 0; i <=this.GetLength() - s.GetLength();i++)
            {
                bool isEqual = true;
                for (int j = i; j < i + s.GetLength(); j++)
                {
                    if(this[j] != s[j - i])
                    {
                        isEqual = false;
                    }
                }
                if (isEqual)
                {
                    return i;
                }
                else
                {
                    continue;
                }
            }
            return -1;
        }

    }

}

namespace _stringStudy
{
class Program
{
static void Main(string[] args)
{
char[] array = new char[] { 'A','B' ,'C'};
Console.WriteLine(new StringDS(array).ToString()); //ABC

StringDS s1 = new StringDS("abc");
StringDS s2 = new StringDS("c");
int j = s1.IndexOf(s2);
Console.WriteLine(j); //2

StringDS s3 = new StringDS("I am a girl");
Console.WriteLine(s3.ToString()); //I am a girl

StringDS s4 = new StringDS("the great");
StringDS s5 = new StringDS(" wall");

Console.WriteLine(s3.GetLength()); //11
Console.WriteLine(s4.GetLength()); //9
Console.WriteLine(s5.GetLength()); // 4

StringDS s6 = s3.SubString(7, 4);
Console.WriteLine(s6.ToString()); //girl

StringDS s7 = s4.SubString(3, 2);
Console.WriteLine(s7.ToString()); // g

Console.WriteLine(StringDS.Concat(s4, s5).ToString());//the great wall

Console.WriteLine(s4.Compare(new StringDS("the")));//1
Console.WriteLine(s4.Compare(new StringDS("a")));//1
Console.WriteLine(s4.Compare(new StringDS("z")));//-1
Console.WriteLine(s4.Compare(new StringDS("the great")));//0
Console.WriteLine(s5.Compare(new StringDS(" wall")));//0

Console.WriteLine(s3.IndexOf(new StringDS("girl"))); //7
Console.WriteLine(s4.IndexOf(new StringDS("the"))); //0
Console.ReadKey();

}
}
}

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