diff --git a/step8.cpp b/step8.cpp
new file mode 100644
index 0000000..6569c29
--- /dev/null
+++ b/step8.cpp
@@ -0,0 +1,140 @@
+#include <stdio.h>
+#include <string.h>
+struct Message
+{
+	char Id[6];
+	char clas[3];
+	char name[10];
+	double score1;
+	double score2;
+	double score3;
+	double score;
+}student[10];
+int sum=0;
+int main(){
+	void MENU();
+	void INPUT(int i);
+	void DELETE();
+	void SELECT();
+	void SORT();
+	void PRINT(int sum);
+	int choose;
+	MENU();
+	scanf("%d",&choose);
+	while(choose!=6){
+		MENU();
+		if(choose==1){
+			INPUT(0);
+		} 
+		else if(choose==2){
+			DELETE();
+		}
+		else if(choose==3){
+			SELECT();
+		}
+		else if(choose==4){
+			SORT();
+		}
+		else {
+			PRINT(sum);
+		}
+		scanf("%d",&choose);	
+	}
+}
+void MENU(){
+	printf("1.input\n2.delete\n3.select\n4.order\n5.output\n6.quit\n");
+	printf("please input your option\n");
+}
+void PRINT(int sum){
+	int i;
+	for(i=0;i<=sum;i++){
+		printf("%s,%s,%s,%.1lf,%.1lf,%.1lf,%.1lf\n",student[i].Id,student[i].clas,student[i].name,student[i].score1,student[i].score2,student[i].score3,student[i].score);	
+		}
+}
+int RESPONSE(){
+	printf("continue?\n");
+	char approve[5]="yes";
+	char response[5];
+	scanf("%s",response);
+	if(strcmp(response,approve)==0)
+		return 1;
+	else
+		return 0;
+}
+int INPUT(int i){
+	printf("Id ");
+	scanf("%s",student[i].Id);
+	printf("class ");
+	scanf("%s",student[i].clas);
+	printf("name ");
+	scanf("%s",student[i].name);
+	printf("score1 ");
+	scanf("%lf",&student[i].score1);
+	printf("score2 ");
+	scanf("%lf",&student[i].score2);
+	printf("score3 ");
+	scanf("%lf",&student[i].score3);
+	int word=RESPONSE();
+	if(word){
+		sum++;
+		INPUT(i+1);
+	}
+	student[i].score=student[i].score1+student[i].score2+student[i].score3;
+	return 0;
+}
+void DELETE(){
+	char input[10];
+	int i,t=0;
+	scanf("%s",input);
+	for(i=0;i<=sum;i++){
+		if(strcmp(student[i].Id,input)==0||strcmp(student[i].name,input)==0){
+			t=1;
+			break;
+		}
+	}
+	if(t==0){
+		PRINT(sum);
+		}
+	else{
+		while(i<sum){
+			student[i]=student[i+1];
+			i++;
+		}
+		sum--;
+		PRINT(sum);
+	}
+	int word=RESPONSE();
+	if(word){
+		DELETE();
+	}
+}
+void SELECT(){
+	char input[6];
+	int i;
+	scanf("%s",input);
+	for(i=0;i<=sum;i++){
+		if(strcmp(student[i].Id,input)==0||strcmp(student[i].clas,input)==0){
+			printf("%s,%s,%s,%.1lf,%.1lf,%.1lf,%.1lf\n",student[i].Id,student[i].clas,student[i].name,student[i].score1,student[i].score2,student[i].score3,student[i].score);
+		}
+	}
+	int word=RESPONSE();
+	if(word){
+		SELECT();
+	}
+}
+void SORT(){
+	int i,j;
+	for(i=1;i<=sum;i++){
+		for(j=0;j<sum+1-i;j++){
+			if(strcmp(student[j].clas,student[j+1].clas)>0){
+				struct Message temp;
+				temp=student[j];student[j]=student[j+1];student[j+1]=temp;
+			}
+			else if(strcmp(student[j].clas,student[j+1].clas)==0&&student[j].score<student[j+1].score){
+				struct Message temp;
+				temp=student[j];student[j]=student[j+1];student[j+1]=temp;
+			}
+		}
+	}
+	PRINT(sum);
+}