经典的委托排序(深入分析)

对于数值型的排序我们都已经司空见惯了，但我们有时候希望我们的sort()方法能够给任何对象排序，比如某段客户机代码包含currency结构数组或其他的类和结构，就需要对该数组排序。这里我们使用委托并封装这个方法进行比较。

排序我们还是使用经典的冒泡排序，如果数据量较大你可以换为你自己的更高效的排序算法。

先给出整个代码：

public class bubblesorter
{
 public static void sort(object[] sortarray, compareoperation gtmethod)
 {
  for (int i = 0; i < sortarray.length; i++)
  {
   for (int j = 0; j < sortarray.length; j++)
   {
    if (gtmethod(sortarray[j], sortarray[i]))
    {
     object tmp = sortarray[i];
     sortarray[i] = sortarray[j];
     sortarray[j] = tmp;
    }
   }
  }
 }
}
public class employee
{
 private string name;
 private decimal salary;
 public employee(string name, decimal salary)
 {
  this.name = name;
  this.salary = salary;
 }
 public override string tostring()
 {
  return string.format(name.padright(20) + "{0:c}", salary);
 }
 public static bool rsalaryisgreater(object lobj, object robj)
 {
  employee lemployee = lobj as employee;
  employee remployee = robj as employee;
  return remployee.salary > lemployee.salary;
 }
}

再给一个调用示例：

public delegate bool compareoperation(object lobj, object robj);
class program
{
 static void main(string[] args)
 {
  employee[] employees =
  {
   new employee("tommy",20000),
   new employee("elmer",10000),
   new employee("daffy", 25000),
   new employee("wiley",1000000),
   new employee("foghorn",23000),
   new employee("roadrunner",50000),
  };
  compareoperation employeecompareoperation = new compareoperation(employee.rsalaryisgreater);
  bubblesorter.sort(employees, employeecompareoperation);
  for (int i = 0; i < employees.length; i++)
  {
   console.writeline(employees[i].tostring());
  }
 }
}