diff --git a/task 5.c b/task 5.c
new file mode 100644
index 0000000..22ebfbe
--- /dev/null
+++ b/task 5.c	
@@ -0,0 +1,100 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+struct Student{
+		char stunumber[5];
+		int class;
+		char name[10];
+		float grade1;
+		float grade2;
+		float grade3;
+		float sum;
+		}students[3]={{"10001",11,"Zhang",99.5,88.5,89.5,99.5+88.5+99.5},
+			{"10002",12,"Yang",77.9,56.5,87.5,77.9+56.5+87.5},
+			{"10003",11,"Liang",92.5,99.0,60.5,92.5+99.0+60.5}};
+void selection_sort(struct Student arr[], int n) {
+    int i, j, min_idx;
+    //一一检索每个结构体中class的值 
+    for (i = 0; i < n-1; i++) {
+        // 找到最小值的位置 
+        min_idx = i;
+        for (j = i+1; j < n; j++)
+        {
+		
+            if (arr[j].class < arr[min_idx].class)
+            {
+                min_idx = j;
+       		}
+       		else if(arr[j].class == arr[min_idx].class)
+       		{
+       			if(arr[j].sum == arr[min_idx].sum)
+       			{
+       				min_idx=j;
+				}
+			}
+		}
+        // 通过交换位置实现排序
+        struct Student temp = arr[min_idx];
+        arr[min_idx] = arr[i];
+        arr[i] = temp;
+    }
+}
+// 打印学生信息
+void print_student(struct Student arr[]) {
+	for(int i=0;i < 3;i++)
+    	printf("%s %d %s %.1f %.1f %.1f \n", students[i].stunumber, students[i].class, students[i].name, students[i].grade1, students[i].grade2, students[i].grade3);
+}
+int main()
+{
+		int n=3;
+		void selection_sort(struct Student arr[], int n); 
+		selection_sort(students,3);//排序 
+		
+		printf("Are you sure(yes/no)?\n");
+    	char ans;
+    	scanf("%s", &ans);
+	    if(ans != 'y') {
+	        // 用户不确认删除
+	        printf("Sorted Students:\n");
+	    	for(int i = 0; i < 3; i++) {
+	        printf("%s %d %s %.1f %.1f %.1f \n", students[i].stunumber, students[i].class, students[i].name, students[i].grade1, students[i].grade2, students[i].grade3);
+			 
+			}	
+			return 0;
+	    }
+	    printf("Enter student number or name to be deleted: ");
+	    char num_or_name[10];
+	    scanf("%s", num_or_name);
+	
+	    // 查找要删除的学生索引
+	    int target_idx = -1;
+	    for(int i = 0; i < 3; i++) {
+	        if(strcmp(num_or_name, students[i].stunumber) == 0 || strcmp(num_or_name, students[i].name) == 0) {
+	            target_idx = i;
+	            break;
+	        }
+	    }
+	    if(target_idx == -1) {
+    		printf("The student does not exist!\n");
+    		// 输出所有学生信息
+    		for(int i = 0; i < 3; i++) {
+        		printf("%s %d %s %.1f %.1f %.1f \n", students[i].stunumber, students[i].class, students[i].name, students[i].grade1, students[i].grade2, students[i].grade3);
+			 
+			}
+			return 0;
+    	}
+    			
+		
+		// 移除目标学生
+	    memmove(&students[target_idx], &students[target_idx + 1], sizeof(students) * (3 - target_idx - 1));
+	
+	    // 输出移除后学生信息
+	    printf("Students after deletion:\n");
+	    for(int i = 0; i < 2; i++) {
+	        printf("%s %d %s %.1f %.1f %.1f \n", students[i].stunumber, students[i].class, students[i].name, students[i].grade1, students[i].grade2, students[i].grade3);
+		}
+	    return 0;
+}
+	
+