C#词法分析求解

C#词法分析求解，请教各位
 private void 开始分析ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            string[] keyword ={"auto","double","int","break","else","long","switch" ,"case" ,"register","typedef","char","extern","return ","union","const" ,"float" ,"short","unsigned","continue","for","signed","void","default",
                "goto","sizeof","volatile","do","while","static" ,"if","printf"};//关键字/保留字
            string[] operatorcharter = { "+", "-", "==", "*", "/", "<", ">", "<=", ">=", "=", "!=", "++", "--" };//运算符
            string[] operatorinterface = { "(", ")", "[", "]", "{", "}", ",", ":", ";", "\"", "*/", "/*" };//介符
            int i;
            string[] a;
            int k=0;
            for (i = 0; i <= richTextBox1.Text.Length; i++)
            { int j = 0;
                if (richTextBox1.Text[i] ="") break ;
                else 
                    while (richTextBox1.Text[i] !="") {
                        a[j] = richTextBox1.Text[i];
                        j++;
                        i++;
                    }
                if (a[j] == keyword) { richTextBox2.Text = "k++        a[j]        关键字"; }
                else if (a[j] == operatorcharter) { richTextBox2.Text = "k++        a[j]        运算符"; }
                else if (a[j] == operatorinterface) { richTextBox2.Text = "k++        a[j]        介符"; }
                else { richTextBox2.Text = "k        a[j]        标识符"; }
           }
        }



【我想知道把单词或其他分析出来该怎么写】
------解决方案--------------------
搜索下盘古分词
------解决方案--------------------
这段代码你是哪里搞来的？运行过吗？是跑不通的吧，没有实例的对象a直接复制会数组越界的