diff --git a/xjxt6.cpp b/xjxt6.cpp
new file mode 100644
index 0000000..18c421e
--- /dev/null
+++ b/xjxt6.cpp
@@ -0,0 +1,83 @@
+#include <stdio.h>
+#include <string.h>
+typedef struct
+{
+	int id;
+	int mclass;
+	char name[20];
+	float a,b,c;
+	float total;
+}Student;
+void sort(Student *person,int len)
+{
+	int i;
+	int j;
+	for(i=0;i<len;i++)
+	{
+		int k=i;
+		for(j=i;j<len;j++)
+		{
+			if(person[k].mclass>person[j].mclass||(person[k].mclass==person[j].mclass&&person[k].total<person[j].total))
+			{
+				k=j;
+			}
+			if(k!=i)
+			{
+				Student temp=person[i];
+				person[i]=person[k];
+				person[k]=temp;
+			}
+		}
+	}
+}
+void modify(Student *person,int len,Student modifyperson)
+{
+	int i;
+	for(i=0;i<len;i++)
+	{
+		if(person[i].id==modifyperson.id)
+		{
+			person[i]=modifyperson;
+			sort(person,3);
+			return;
+		}
+	}
+}
+void print(Student *person,int len,Student modifyperson)
+{
+	int classname=0;
+	int i;
+	for(i=0;i<len;i++)
+	{
+		if(person[i].mclass!=classname)
+		{
+			classname=person[i].mclass;
+			printf("%d ",classname);
+		}else{
+			printf("   ");
+		}
+		printf("%d %s %.1f %.1f %.1f",person[i].id,person[i].name,person[i].a,person[i].b,person[i].c);
+		if(person[i].id==modifyperson.id)
+		{
+			printf(" modified");
+		}
+		printf("\n");
+	}
+}
+int main()
+{
+	Student students[]=
+	{
+		{10001,11,"Zhang",99.5,88.5,89.5},
+        {10002,12,"Yang",77.9,56.5,87.5},
+		{10003,11,"Liang",92.5,99.0,60.5}
+	};
+	sort(students,3);
+	Student modifystudent;
+	scanf("%d %d %s %f %f %f",&modifystudent.id,&modifystudent.mclass,&modifystudent.name,&modifystudent.a,&modifystudent.b,&modifystudent.c);
+	sort(students,3);
+	modify(students,3,modifystudent);
+	print(students,3,modifystudent);
+	return 0;
+}
+