diff --git a/xjxt4.cpp b/xjxt4.cpp
new file mode 100644
index 0000000..c092a80
--- /dev/null
+++ b/xjxt4.cpp
@@ -0,0 +1,70 @@
+#include <stdio.h>
+typedef struct{
+	int Id;
+	int mclass;
+	float a,b,c;
+	float total;
+}Student;
+void sort(Student *person,int len)
+{
+	for(int i=0;i<len-1;i++)
+	{
+		int k=i;
+		for(int j=i;j<len-1;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;
+			}
+		}
+	}
+}
+int newId,newClass;
+float grade1,grade2,grade3;
+void print(Student *person)
+{
+	for(int i=0;i<4;i++)
+	{
+		printf("%d %d %.lf %.lf %.lf",person[i].Id,person[i].mclass,person[i].a,person[i].b,person[i].c);
+	    if(person[i].Id==newId)
+	    {
+	    	printf(" inserted");
+		}
+		printf("\n");
+	}
+}
+int main()
+{
+	Student students[4]=
+	{
+        {10001,11,99.5,88.5,89.5,99.5+88.5+89.5},
+        {10002,12,77.9,56.5,87.5,77.9+56.5+87.5},
+        {10003,11,92.5,99.0,60.5,92.5+99.0+60.5},
+        {10000,0,0.0,0.0,0.0,0.0}
+    };
+    scanf("%d %d %f %f %f",&newId,&newClass,&grade1,&grade2,&grade3);
+    for(int i=0;i<3;i++)
+    {
+    	if(students[i].Id==newId)
+    	{
+    		printf("The student id %d already exists.\n",newId);
+    		return 0;
+		}
+	}
+	students[3].Id=newId;
+    students[3].mclass=newClass;
+    students[3].a=grade1;
+    students[3].b=grade2;
+    students[3].c=grade3;
+    students[3].total=grade1+grade2+grade3;
+    sort(students,4);
+    print(students);
+    return 0;
+}
+