public class car : IComparable
{
// Beginning of nested classes. // Nested class to do ascending sort on year property.
private class sortYearAscendingHelper: IComparer
{
int IComparer.Compare(object a, object b)
{
car c1=(car)a;
car c2=(car)b; if (c1.year > c2.year)
return 1; if (c1.year < c2.year)
return -1; else
return 0;
}
}问题:为什么有car c1=(car)a;
car c2=(car)b;这两句在程序里有什么作用啊??如果不写可以吗??
{
// Beginning of nested classes. // Nested class to do ascending sort on year property.
private class sortYearAscendingHelper: IComparer
{
int IComparer.Compare(object a, object b)
{
car c1=(car)a;
car c2=(car)b; if (c1.year > c2.year)
return 1; if (c1.year < c2.year)
return -1; else
return 0;
}
}问题:为什么有car c1=(car)a;
car c2=(car)b;这两句在程序里有什么作用啊??如果不写可以吗??
解决方案 »
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