static void Main(string[] args)
{
int y=0,l=0,z=0,jg=0,bjg=0;
double score;
char judge;
do
{
Console.WriteLine("请输入学生成绩:");
score=double.Parse(Console.ReadLine());
if(score>=90&&score<=100)
y++;
else if(score>=80&&score<=89)
l++;
else if(score>=70&&score<=79)
z++;
else if(score>=60&&score<=69)
jg++;
else
bjg++;
Console.WriteLine("请问你还要继续输入成绩吗?y/n");
judge=char.Parse(Console.ReadLine());
}while(judge=='y'||judge=='Y');
Console.WriteLine("优秀{0}人,良好{1}人,中等{2}人,及格{3}人,不及格{4}人",y,l,z,jg,bjg);
Console.ReadLine();
}