diff --git a/ModifyInfo.c b/ModifyInfo.c
new file mode 100644
index 0000000..b753545
--- /dev/null
+++ b/ModifyInfo.c
@@ -0,0 +1,55 @@
+#include "mysyslib.h"
+
+typedef struct Student
+{
+	char* id;
+	char* clas;
+	char* name;
+	double score1;
+	double score2;
+	double score3;
+	double score;
+}student;
+
+void ModifyInfo(Student stu_info[],int len)
+{
+	Student new_stu_info;
+	scanf("%s%s%s%lf%lf%lf", new_stu_info.id, new_stu_info.clas, new_stu_info.name, new_stu_info.score1, new_stu_info.score2, new_stu_info.score3);
+	for (int i = 0; i < len; i++) {
+		if (strcmp(new_stu_info.id, stu_info[i].id) == 0) {
+			stu_info[i] = new_stu_info;
+		}
+	}
+	char* max, min;
+	strcpy(max, stu_info[0].clas);
+	strcpy(min, stu_info[0].clas);
+	for (int i = 0; i < len; i++) {
+		if (stu_info[i].clas > max) {
+			strcpy(max, stu_info[i].clas);
+		}
+		if (stu_info[i].clas < min) {
+			strcpy(min, stu_info[i].clas);
+		}
+	}
+	int i = 0, flag = 0;
+	while (strcmp(min, max) != 1) {
+		while (i < len && strcmp(min, stu_info[i++].clas) == 0) {
+			if (flag == 1) {
+				if (strcmp(stu_info[i].id, new_stu_info.id) == 0) {
+					printf("   %s %s %lf %lf %lf modified\n", stu_info[i].id, stu_info[i].name, stu_info[i].score1, stu_info[i].score2, stu_info[i].score3);
+				}
+				else
+					printf("   %s %s %lf %lf %lf\n", stu_info[i].id, stu_info[i].name, stu_info[i].score1, stu_info[i].score2, stu_info[i].score3);
+			}
+			else {
+				flag = 1;
+				if (strcmp(stu_info[i].id, new_stu_info.id) == 0) {
+					printf("%s %s %s %lf %lf %lf modified\n", stu_info[i].clas, stu_info[i].id, stu_info[i].name, stu_info[i].score1, stu_info[i].score2, stu_info[i].score3);
+				}
+				else
+					printf("%s %s %s %lf %lf %lf modified\n", stu_info[i].clas, stu_info[i].id, stu_info[i].name, stu_info[i].score1, stu_info[i].score2, stu_info[i].score3);
+			}
+		}
+		min = min + 1;
+	}
+}
diff --git a/delete.c b/delete.c
deleted file mode 100644
index d969d58..0000000
--- a/delete.c
+++ /dev/null
@@ -1,20 +0,0 @@
-#include "mysyslib.h"
-
-void cancel(ss*stu){
-  char* tmp = (char*)malloc(sizeof(char)*3);
-    do{
-        char*ID = (char*)malloc(sizeof(char)*6);
-        scanf("%s",ID);
-        for(int i = 0; i < stu->nums; ++i){
-            if(strcmp(stu->student[i].id,ID) == 0){
-                for(int j = i; j < stu->nums-1; ++j){
-                    stu->student[j] = stu->student[j+1];
-                }
-            }
-        }
-        stu->nums--;
-        allPrint(stu);
-        printf("continue?\n");
-        scanf("%s",tmp);
-    }while(!strcmp(tmp,"yes"));
-}
diff --git a/init.c b/init.c
index 704ec37..69c7b90 100644
--- a/init.c
+++ b/init.c
@@ -10,9 +10,8 @@ w#include "mysyslib.h"
 
      for(int i = 0; i < Nums; ++i){
          stu->student[i].id = (char*)malloc(sizeof(char)*6);
-         stu->student[i].class = (char*)malloc(sizeof(char)*3);
+         stu->student[i].clas = (char*)malloc(sizeof(char)*3);
          stu->student[i].name = (char*)malloc(sizeof(char)*10);
-
      }
      return stu;
  }
diff --git a/main.c b/main.c
index 020a8e7..bdc3f3b 100644
--- a/main.c
+++ b/main.c
@@ -2,9 +2,9 @@
 
 int main(){
   int ipt;
-  ss* stu = init(6);
+  ss* stu = init(20);
   while(1){
-    if(mainMenu(stu)){
+    if(mainMenu(stus)){
       break;
     }
   }
diff --git a/mysyslib.h b/mysyslib.h
index b678af7..f1a514d 100644
--- a/mysyslib.h
+++ b/mysyslib.h
@@ -4,7 +4,7 @@
 
 typedef struct{
     char *id;
-    char *class;
+    char *clas;
     char *name;
     double score1;
     double score2;
diff --git a/operations.c b/operations.c
new file mode 100644
index 0000000..32ed5b1
--- /dev/null
+++ b/operations.c
@@ -0,0 +1,120 @@
+#include "mysyslib.h"
+
+//录入数据
+void input(ss*stu){
+    char tmp[5];
+    do{
+        int pst = stu->nums;
+        printf("Id  ");
+        scanf(" %s",stu->student[pst].id);
+        printf("\n");
+        
+        printf("class  ");
+        scanf(" %s",stu->student[pst].clas);
+        printf("\n");
+        
+        printf("name  ");
+        scanf(" %s",stu->student[pst].name);
+        printf("\n");
+        
+        printf("score1  ");
+        scanf("%lf",&stu->student[pst].score1);
+        printf("\n");
+        
+        printf("score2  ");
+        scanf("%lf",&stu->student[pst].score2);
+        printf("\n");
+        
+        printf("score3  ");
+        scanf("%lf",&stu->student[pst].score3);
+        printf("\n");
+        
+        stu->student[pst].score = stu->student[pst].score1 + stu->student[pst].score2 + stu->student[pst].score3;
+        stu->nums++;
+        
+        printf("continue?\n");
+        scanf("%s",tmp);
+    }while(!strcmp(tmp,"yes"));
+    
+    return;
+}
+
+//输出相关
+void Print(Student*student){
+    printf("%s,%s,%s,%.1lf,%.1lf,%.1lf,%.1lf\n",student->id,student->clas,student->name,student->score1,student->score2,student->score3,student->score);
+}
+
+void allPrint(ss*stu){
+  if(stu->nums){
+    for(int i = 0; i < stu->nums; ++i){
+        Print(&stu->student[i]);
+    }
+  }else{
+    printf("No data exist\n");
+  }
+}   
+
+//删除学生信息
+void cancel(ss*stu){
+  char* tmp = (char*)malloc(sizeof(char)*3);
+    do{
+        char*ID = (char*)malloc(sizeof(char)*6);
+        scanf("%s",ID);
+        for(int i = 0; i < stu->nums; ++i){
+            if(strcmp(stu->student[i].id,ID) == 0){
+                for(int j = i; j < stu->nums-1; ++j){
+                    stu->student[j] = stu->student[j+1];
+                }
+            }
+        }
+        stu->nums--;
+        allPrint(stu);
+        printf("continue?\n");
+        scanf("%s",tmp);
+    }while(!strcmp(tmp,"yes"));
+}
+
+//修改学生信息
+void ModifyInfo(Student stu->student[])
+{
+  int len = stu->nums;
+	Student new_stu_info;
+	scanf("%s%s%s%lf%lf%lf", new_stu_info.id, new_stu_info.clas, new_stu_info.name, new_stu_info.score1, new_stu_info.score2, new_stu_info.score3);
+	for (int i = 0; i < len; i++) {
+		if (strcmp(new_stu_info.id, stu->student[i].id) == 0) {
+			stu->student[i] = new_stu_info;
+		}
+	}
+	char* max, min;
+	strcpy(max, stu->student[0].clas);
+	strcpy(min, stu->student[0].clas);
+	for (int i = 0; i < len; i++) {
+		if (stu->student[i].clas > max) {
+			strcpy(max, stu->student[i].clas);
+		}
+		if (stu->student[i].clas < min) {
+			strcpy(min, stu->student[i].clas);
+		}
+	}
+	int i = 0, flag = 0;
+	while (strcmp(min, max) != 1) {
+		while (i < len && strcmp(min, stu->student[i++].clas) == 0) {
+			if (flag == 1) {
+				if (strcmp(stu->student[i].id, new_stu_info.id) == 0) {
+					printf("   %s %s %lf %lf %lf modified\n", stu->student[i].id, stu->student[i].name, stu->student[i].score1, stu->student[i].score2, stu->student[i].score3);
+				}
+				else
+					printf("   %s %s %lf %lf %lf\n", stu->student[i].id, stu->student[i].name, stu->student[i].score1, stu->student[i].score2, stu->student[i].score3);
+			}
+			else {
+				flag = 1;
+				if (strcmp(stu->student[i].id, new_stu_info.id) == 0) {
+					printf("%s %s %s %lf %lf %lf modified\n", stu->student[i].clas, stu->student[i].id, stu->student[i].name, stu->student[i].score1, stu->student[i].score2, stu->student[i].score3);
+				}
+				else
+					printf("%s %s %s %lf %lf %lf modified\n", stu->student[i].clas, stu->student[i].id, stu->student[i].name, stu->student[i].score1, stu->student[i].score2, stu->student[i].score3);
+			}
+		}
+		min = min + 1;
+	}
+}
diff --git a/stuIO.c b/stuIO.c
deleted file mode 100644
index caa5b82..0000000
--- a/stuIO.c
+++ /dev/null
@@ -1,54 +0,0 @@
-#include "mysyslib.h"
-
-void input(ss*stu){
-    char tmp[5];
-    do{
-        int pst = stu->nums;
-        printf("Id  ");
-        scanf(" %s",stu->student[pst].id);
-        printf("\n");
-        
-        printf("class  ");
-        scanf(" %s",stu->student[pst].class);
-        printf("\n");
-        
-        printf("name  ");
-        scanf(" %s",stu->student[pst].name);
-        printf("\n");
-        
-        printf("score1  ");
-        scanf("%lf",&stu->student[pst].score1);
-        printf("\n");
-        
-        printf("score2  ");
-        scanf("%lf",&stu->student[pst].score2);
-        printf("\n");
-        
-        printf("score3  ");
-        scanf("%lf",&stu->student[pst].score3);
-        printf("\n");
-        
-        stu->student[pst].score = stu->student[pst].score1 + stu->student[pst].score2 + stu->student[pst].score3;
-        stu->nums++;
-        
-        printf("continue?\n");
-        scanf("%s",tmp);
-    }while(!strcmp(tmp,"yes"));
-    
-    return;
-}
-
-//输出相关
-void Print(Student*student){
-    printf("%s,%s,%s,%.1lf,%.1lf,%.1lf,%.1lf\n",student->id,student->class,student->name,student->score1,student->score2,student->score3,student->score);
-}
-
-void allPrint(ss*stu){
-  if(stu->nums){
-    for(int i = 0; i < stu->nums; ++i){
-        Print(&stu->student[i]);
-    }
-  }else{
-    printf("No data exist\n");
-  }
-}