diff --git a/4，5.cpp b/4，5.cpp
new file mode 100644
index 0000000..7dfa658
--- /dev/null
+++ b/4，5.cpp
@@ -0,0 +1,60 @@
+#include<stdio.h>
+int main()
+{
+struct data
+	{
+		long int num;
+		long int clas;
+		char name[20];
+		float grade1;
+		float grade2;
+		float grade3;
+	}; 
+	struct data stud[3]={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 data stu;//{10001,11,"zhang",99,88,89};
+	printf("ÇëÊäÈë´ýÐ޸ĵÄѧÉúÐÅÏ¢\n"); 
+	scanf("%ld %ld %s %f %f %f",&stu.num,&stu.clas,&stu.name,&stu.grade1,&stu.grade2,&stu.grade3);
+    for(int i=0;i<3;i++)
+    {
+    	if(stu.num==stud[i].num)
+    	{
+    		stud[i].grade1=stu.grade1;
+    		stud[i].grade2=stu.grade2;
+    		stud[i].grade3=stu.grade3;
+		}
+		break;
+	}
+	struct data temp;
+	for(int i=0;i<3;i++)
+	{
+		for(int j=i+1;j<3;j++)
+		{
+			if(stud[i].clas>stud[j].clas)
+			{
+				temp=stud[i];
+				stud[i]=stud[j];
+				stud[j]=temp;
+			}
+		}
+	}
+	for(int i=0;i<3;i++)
+	{
+		for(int j=i+1;j<3;j++)
+		{
+			if(stud[i].num>stud[j].num&&stud[i].clas==stud[j].clas)
+			{
+				temp=stud[i];
+				stud[i]=stud[j];
+				stud[j]=temp;
+			}
+		}
+	}
+	for(int i=0;i<3;i++)
+	{
+		if(i>0&&stud[i].clas==stud[i-1].clas) 
+		printf("   %ld %s %3.1f %3.1f %3.1f",stud[i].num,stud[i].name,stud[i].grade1,stud[i].grade2,stud[i].grade3);
+		else printf("%d %ld %s %3.1f %3.1f %3.1f",stud[i].clas,stud[i].num,stud[i].name,stud[i].grade1,stud[i].grade2,stud[i].grade3);
+		if(stud[i].num==stu.num) printf(" modified");
+		printf("\n");
+	}
+	return 0;}