diff --git a/8.cpp b/8.cpp
new file mode 100644
index 0000000..09a4740
--- /dev/null
+++ b/8.cpp
@@ -0,0 +1,166 @@
+#include <stdio.h>
+#include <time.h>
+#include <stdlib.h>
+#include <string.h>
+void input();
+void delete1();
+void select();
+void order();
+void output();
+void quit();
+void menu();
+int sum=0;
+
+struct stu
+{
+	int Id;
+	int clas;
+	char name[10];
+	float score1;
+	float score2;
+	float score3;
+	float score;
+}stu[1000];
+int main()
+{
+	while(1)
+	{
+		menu();
+	}
+}
+void menu()
+{
+	printf("                              1.Input\n");
+	printf("                              2.delete\n");
+	printf("                              3.select\n");
+	printf("                              4.order\n");
+	printf("                              5.output\n");
+	printf("                              6.quit\n");
+	printf("                              please input your option\n");
+	int t;
+	scanf("%d",&t);
+	switch(t)
+	{
+		case 1:input();break;
+		case 2:delete1();break;
+		case 3:select();break;
+		case 4:order();break;
+		case 5:output();break;
+		case 6:quit();break;
+	}	
+}
+void input()
+{
+	sum=sum+1;
+	printf("Id ");
+	scanf("%d",&stu[sum].Id);
+	printf("class ");
+	scanf("%d",&stu[sum].clas);
+	printf("name ");
+	scanf("%s",&stu[sum].name);
+	printf("score1 ");
+	scanf("%f",&stu[sum].score1);
+	printf("score2 ");
+	scanf("%f",&stu[sum].score2);
+	printf("score3 ");
+	scanf("%f",&stu[sum].score3);
+	stu[sum].score=stu[sum].score3+stu[sum].score2+stu[sum].score1;
+	printf("continue?\n");
+	char a[10];
+	scanf("%s",&a);
+	if(a[0]=='y'&&a[1]=='e'&&a[2]=='s')
+	{
+		input();
+	}
+	else if(a[0]=='n'&&a[1]=='o')
+	{
+		menu();
+	}
+}
+void delete1()
+{
+	char b[10];
+	scanf("%s",&b);
+	int c=0,len=strlen(b);
+	for(int k=0;k<len;k++)
+	{
+		c=c*10+b[k]-'0';
+	}
+	if(sum>1)
+	{
+		for(int i=1;i<=sum;i++)
+		{
+			if(stu[i].Id==c||stu[i].name==b)
+			{
+				for(int j=i;j<=sum;j++)
+				{
+					stu[j]=stu[j+1];
+					sum=sum-1;
+				}
+			}
+		}
+	}
+	else
+	{
+	printf("can t");
+	}
+	output();
+}
+void select()
+{
+	int b;
+	scanf("%d",&b);
+	for(int i=1;i<=sum;i++)
+	{
+		if(stu[i].Id==b||stu[i].clas==b)
+		{
+			printf("%d %d %s %f %f %f %f\n",stu[i].Id,stu[i].clas,stu[i].name,stu[i].score1,stu[i].score2,stu[i].score3,stu[i].score) ;
+		}
+	}
+	char a[10];
+	scanf("%s",&a);
+	if(a[0]=='y'&&a[1]=='e'&&a[2]=='s')
+	{
+		select();
+	}
+	else if(a[0]=='n'&&a[1]=='o')
+	{
+		menu();
+	}
+}
+void order()
+{
+	for(int i=1;i<=sum;i++)
+	{
+		for(int j=i;j<=sum;j++)
+		{
+			if(stu[i].clas>stu[j].clas)
+			{
+				stu[sum+1]=stu[i];
+				stu[i]=stu[j];
+				stu[j]=stu[sum+1];
+			}
+			else if(stu[i].clas==stu[j].clas)
+			{
+				if(stu[i].Id>stu[j].Id)
+				{
+					stu[sum+1]=stu[i];
+					stu[i]=stu[j];
+					stu[j]=stu[sum+1];
+				}
+			}
+		}
+	}
+}
+void output()
+{
+	for(int i=1;i<=sum;i++)
+	{
+		printf("%d %d %s %f %f %f %f\n",stu[i].Id,stu[i].clas,stu[i].name,stu[i].score1,stu[i].score2,stu[i].score3,stu[i].score);
+	}
+	menu();	
+}
+void quit()
+{
+	exit(0);
+}