diff --git a/T6chang.cpp b/T6chang.cpp
new file mode 100644
index 0000000..e1db9c7
--- /dev/null
+++ b/T6chang.cpp
@@ -0,0 +1,83 @@
+#include <stdio.h>
+struct stud
+	{
+		int num;
+		int clas;
+		char name[10]; 
+		float math;
+		float phy;
+		float eng;
+		char modf;
+	};
+int main()
+{
+	
+	struct stud stu[10]={{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},
+	};
+	struct stud t={};
+	struct stud ch[1];
+	scanf("%d %d %s %f %f %f",&ch[0].num,&ch[0].clas,ch[0].name,&ch[0].math,&ch[0].phy,&ch[0].eng);
+	struct stud*p=stu;
+	struct stud*p1=ch;
+	void change(struct stud stu[],struct stud ch[]);
+	change(p,p1);
+	int i,j;
+	for(i=0;stu[i].num!=0;i++)
+	{
+		if(stu[i+1].num!=0)
+		{
+			for(j=i+1;stu[j].num!=0;j++)
+			{
+				if(stu[i].clas>stu[j].clas)
+				{
+					t=stu[i];stu[i]=stu[j];stu[j]=t;
+				}
+			}
+		}
+	}
+	for(i=0;stu[i].num!=0;i++)
+	{
+		if(stu[i+1].num!=0)
+		{
+			for(j=i+1;stu[j].num!=0&&stu[i].clas==stu[j].clas;j++)
+			{
+				if(stu[i].math+stu[i].phy+stu[i].eng<stu[j].math+stu[j].phy+stu[j].eng)
+				{
+					t=stu[i];stu[i]=stu[j];stu[j]=t;
+				}
+			}
+		}
+	}
+	for(i=0;stu[i].num!=0;i++)
+	{
+		if(i==0)printf("%d %d %s %3.1f %3.1f %3.1f",stu[i].clas,stu[i].num,stu[i].name,stu[i].math,stu[i].phy,stu[i].eng);
+		else
+		{
+			if(stu[i].clas==stu[i-1].clas)
+			{
+				printf("   %d %s %3.1f %3.1f %3.1f",stu[i].num,stu[i].name,stu[i].math,stu[i].phy,stu[i].eng);
+			}	
+			else printf("%d %d %s %3.1f %3.1f %3.1f",stu[i].clas,stu[i].num,stu[i].name,stu[i].math,stu[i].phy,stu[i].eng);
+		}
+		if(stu[i].modf=='y')
+		{printf(" modified");}
+		printf("\n");	
+	}
+	return 0;
+}
+void change(struct stud stu[],struct stud ch[])
+{
+	int i;
+	for(i=0;stu[i].num!=0;i++)
+	{
+		if(stu[i].num==ch[0].num)
+		{
+			stu[i]=ch[0];
+			stu[i].modf='y';
+			break;		
+		}
+	}
+	
+}