diff --git a/作业2.8.c b/作业2.8.c
new file mode 100644
index 0000000..e88ed8c
--- /dev/null
+++ b/作业2.8.c
@@ -0,0 +1,131 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+typedef struct Student{
+	char *id;
+	int cl;
+	char *name;
+	float score1;
+    float score2;
+    float score3;
+    float total_score;
+}Student;
+void mainmenu(){
+	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");
+}
+void inputStudentinfo(Student *students,int *size){
+	printf("Id ");
+    students[*size].id=(char *)malloc(sizeof(char)*10);
+    scanf("%s",students[*size].id);
+    printf("class ");
+    scanf("%d",&students[*size].cl);
+    printf("name ");
+    students[*size].name=(char *)malloc(sizeof(char)*10);
+    scanf("%s",students[*size].name);
+    printf("score1 ");
+    scanf("%f",&students[*size].score1);
+    printf("score2 ");
+    scanf("%f",&students[*size].score2);
+    printf("score3 ");
+    scanf("%f",&students[*size].score3);
+    (*size)++;
+}
+void deleteinfo(Student* students, int* size) {
+    char id[10];
+    scanf("%s",id);
+    int i;
+    for (i=0;i<*size;++i) {
+    	if (strcmp(students[i].id,id) == 0) {
+            free(students[i].id);
+            free(students[i].name);
+            students[i]=students[--(*size)];
+            return;
+        }
+    }
+}
+void select(Student* students,int size){
+    char id[10];
+    scanf("%s",id);
+    int i;
+    for (i=0;i<size;++i){
+        if(strcmp(students[i].id,id)==0){
+            printf("%s %d %s %.2f %.2f %.2f\n", students[i].id, students[i].cl, students[i].name, students[i].score1, students[i].score2, students[i].score3);
+            return;
+        }
+    }
+}
+void sort(Student* students,int size) {
+    int i,j;
+    for(i=0;i<size - 1;++i) {
+        for(j=0;j<size-1-i;++j) {
+            if(students[j].cl>students[j + 1].cl){
+                Student temp=students[j];
+                students[j]=students[j + 1];
+                students[j + 1]=temp;
+            }
+        }
+    }
+}
+void output(Student* students,int size){
+    int i;
+    for(i=0;i<size;++i) {
+        printf("%s %d %s %.2f %.2f %.2f\n", students[i].id, students[i].cl, students[i].name, students[i].score1, students[i].score2, students[i].score3);
+    }
+}
+int main(){
+	Student students[100];
+    int size=0;
+    int option;
+    int lastop=-1;
+    char continueFlag[10];
+    int runflag=1;
+    while(runflag){
+    	mainmenu();
+        if(lastop==-1){
+        	scanf("%d",&option);
+		}else{
+			option=lastop;
+		}
+		do{
+			switch (option) {
+        	case 1:
+            	inputStudentinfo(students,&size);
+            	break;
+        	case 2:
+            	deleteinfo(students,&size);
+            	break;
+        	case 3:
+            	select(students,size);
+            	break;
+        	case 4:
+            	sort(students,size);
+            	break;
+        	case 5:
+            	output(students,size);
+            	break;
+        	case 6:
+            	runflag=0;  
+                break;
+        	}
+        	if(runflag){
+        		printf("continue?\n");
+            	scanf("%s", continueFlag);
+            	if(strcmp(continueFlag,"yes")==0){
+    				lastop=option;
+				}else{
+					lastop=-1;
+				}
+			} 
+        	
+			
+            
+		}while(strcmp(continueFlag,"yes")==0&&runflag); 
+	}
+	return 0;
+}