diff --git a/step8 b/step8
new file mode 100644
index 0000000..42c3258
--- /dev/null
+++ b/step8
@@ -0,0 +1,162 @@
+#include<stdio.h>
+#include<string.h> 
+struct Student
+{
+	char id[20];
+	char Class[20];
+	char name[50];
+	float gs;
+	float dw;
+	float yy;
+	float all;
+};
+struct Student stu[20];
+int n=0;
+void menu()
+{
+	printf("1.input\n");
+	printf("2.delect\n");
+	printf("3.select\n");
+	printf("4.order\n");
+	printf("5.output\n");
+	printf("6.quit\n");
+	printf("please input your optition\n");
+}
+void print()
+{
+	int i=0;
+	for(i;i<n;i++)
+	{
+		printf("%s,%s,%s,%.1f,%.1f,%.1f,%.1f\n",stu[i].id,stu[i].Class,stu[i].name,stu[i].gs,stu[i].dw,stu[i].yy,stu[i].all);
+	}
+}
+void input()//
+{
+	char ch[20];//chioce选择是否进行继续input操作
+	int i=1;
+	while(i=1)
+	{
+	 printf("Id:");
+	 scanf("%s",&stu[n].id);
+	 printf("Class:");
+	 scanf("%s",&stu[n].Class);
+	 printf("Name:");
+	 scanf("%s",&stu[n].name);
+	 printf("score1:");
+	 scanf("%f",&stu[n].gs);
+	 printf("score2:");
+	 scanf("%f",&stu[n].dw);
+	 printf("score3:");
+	 scanf("%f",&stu[n].yy);
+	 n++;
+	 printf("continue?\n");
+	 scanf("%s",ch);
+	 if(strcmp(ch,"no")==0)
+	 {
+	 	i=0;
+	 	return;
+	 }
+	 else 
+	 {
+	 	i=1;
+	 	ch[20]='\0';//将choice数组中的字符清零以便进行下一次的判断
+	 }
+	 } 
+}
+void del()
+{
+	int i,d;
+	char key[20],op[20];
+	while(1)
+	{
+		i=0,d=0;
+		scanf("%s",key);
+		while(i<n)
+		{
+			if(strcmp((stu+i)->id,key)==0||strcmp((stu+i)->name,key)==0)
+			{
+				d++;n--;
+				*(stu+i)=*(stu+i+d);
+			}
+			else
+			{
+				*(stu+i)=*(stu+i+d);
+				i++;
+			}
+		}
+		print();
+		printf("continue?\n");
+		do{
+			scanf("%s",op);
+		}while(strcmp(op,"yes")!=0&&strcmp(op,"no")!=0);
+		if(strcmp(op,"no")==0) return;
+	}
+}
+
+void select()
+{
+	int i,j;
+	char key[20],op[20];
+	while(1)
+	{
+		j=0;
+		scanf("%s",key);
+		for(i=0;i<n;i++)
+		{
+				if(strcmp((stu+i)->id,key)==0||strcmp((stu+i)->Class,key)==0)
+			{
+				j=1;
+				printf("%s,%s,%s,%.1f,%.1f,%.1f,%.1f\n",stu[i].id,stu[i].Class,stu[i].name,stu[i].gs,stu[i].dw,stu[i].yy,stu[i].all);
+			}
+		}
+		if(j==0)
+		{
+			printf("there is no eligible student\n");
+			return;
+		}
+			printf("continue?\n");
+	do
+	{
+		scanf("%s",op);
+	}
+	while(strcmp(op,"yes")!=0&&strcmp(op,"no")!=0);
+	if(strcmp(op,"no")==0) return;
+	}
+}
+void order()
+{
+	int i,j;
+	struct Student swap;
+	for(i=0;i<n;i++)//对班级排序 
+	{
+		for(j=0;j<n-i-1;j++)
+		{
+			if(strcmp((stu+j)->Class,(stu+j+1)->Class)==1||(strcmp((stu+j)->Class,(stu+j+1)->Class)==0)&&stu[j].all<stu[j].all)
+			{
+				swap=*(stu+j);
+				*(stu+j)=*(stu+j+1);
+				*(stu+j+1)=swap;
+			}
+		}
+	}
+	print();
+	return ;
+}
+int main()
+{
+	int choice;
+	while(1)
+	{
+	  menu();
+	  scanf("%d",&choice);
+	  switch(choice)
+	  {
+	  	case 1:input();break;
+	  	case 2:del();break;
+	  	case 3:select();break;
+	  	case 4:order();break;
+	  	case 5:print();break;
+	  	case 6:return 0;
+	  }
+    }
+}
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