diff --git a/77.c b/77.c
new file mode 100644
index 0000000..5fc7080
--- /dev/null
+++ b/77.c
@@ -0,0 +1,474 @@
+#include<stdio.h>
+#include<string.h>
+#include<stdlib.h>
+#include<malloc.h>
+void prin1();
+void choose();
+typedef struct subjects  //定义课程信息结构体
+{
+	int num; //课程编号
+	char name[20]; //课程名称
+	char kind[10];//课程性质
+	int stime;//总学时
+	int ttime;//授课学时
+	int etime;//实验或上机学时 
+	int score;//学分
+	int term;//开课学期
+	struct subjects *next; 
+ } SUB;
+ SUB *head=NULL;
+  //下面定义链表模块
+ SUB *create_form()
+ {
+ 	SUB *head,*tail,*p;//定义头节点，尾节点，中间节点。 
+ 	int num,stime,ttime;
+ 	int etime,score,term;
+ 	char name[20],kind[10];
+ 	int size=sizeof(SUB);
+ 	head=tail=NULL;
+ 	printf("输入选修课程信息:\n");
+ 	scanf("%d%s%s%d%d%d%d%d",&num,name,kind,&stime,&ttime,&etime,&score,&term);
+ 	while(num!=0)
+ 	{
+ 		p=(SUB *)malloc(size);
+ 		p->num=num;
+ 		strcpy(p->name,name);
+ 		strcpy(p->kind,kind);
+ 		p->stime=stime;
+ 		p->ttime=ttime;
+ 		p->etime=etime;
+ 		p->score=score;
+ 		p->term=term;
+ 		if(head==NULL)
+ 		head=p;
+ 		else
+ 		tail->next=p;
+ 		tail=p;
+ 		scanf("%d%s%s%d%d%d%d%d",&num,name,kind,&stime,&ttime,&etime,&score,&term);
+	 }
+	 tail->next=NULL;
+	 return head;
+  } 
+   //保存文件模块
+  void savefile()   //保存文件
+  {
+  	SUB *p;
+  	FILE *fp;fp=fopen("2.txt","w");
+if(fp==NULL)exit(0);
+printf("课程编号  课程名称  课程性质  总学时  授课学时  实践或上级学时  学分  开课学期\n");
+for(p=head;p;p=p->next)
+fprintf(fp,"%5d%12s%9s%9d%9d%11d%11d%7d\n",p->num,p->name,p->kind,p->stime,p->ttime,p->etime,p->score,p->term);
+fclose(fp);
+printf("创建后信息已放入'2.txt'文件中\n");
+system("pause");}
+void savefile1()
+{
+	SUB *p;
+  	FILE *fp;fp=fopen("3.txt","w");
+if(fp==NULL)exit(0);
+for(p=head;p;p=p->next)
+fprintf(fp,"%5d%12s%9s%9d%9d%11d%11d%7d\n",p->num,p->name,p->kind,p->stime,p->ttime,p->etime,p->score,p->term);
+fclose(fp);
+printf("创建后信息已放入'3.txt'文件中\n");
+system("pause");
+	
+	
+}
+  //读取文件模块
+ void readfile()//阅读文件
+ {
+ 	void *myInsert(SUB*);
+	 SUB *newSub;//新课程
+	 int num,stime,ttime,etime;
+	 int score,term;
+	 char c,name[20],kind[10],fname[20];
+	 FILE *fp;
+	 fp=fopen("2.txt","r");
+	 while(!feof(fp))
+	 {
+	 	newSub=(SUB*)malloc(sizeof(SUB));
+	 	fscanf(fp,"%d%s%s%d%d%d%d%d\n",&newSub->num,newSub->name,newSub->kind,&newSub->stime,&newSub->ttime,&newSub->etime,&newSub->score,&newSub->term);
+	 	myInsert(newSub);
+	  } 
+	  fclose(fp);
+  } 
+  void read()
+  {
+ 	void *myInsert(SUB*);
+	 SUB *newSub;//新课程
+	 int num,stime,ttime,etime;
+	 int score,term;
+	 char c,name[20],kind[10],fname[20];
+	 FILE *fp;
+	 fp=fopen("3.txt","r");
+	 while(!feof(fp))
+	 {
+	 	newSub=(SUB*)malloc(sizeof(SUB));
+	 	fscanf(fp,"%d%s%s%d%d%d%d%d\n",&newSub->num,newSub->name,newSub->kind,&newSub->stime,&newSub->ttime,&newSub->etime,&newSub->score,&newSub->term);
+	 	myInsert(newSub);
+	  } 
+	  fclose(fp);
+  } 
+  //下面定义浏览模块
+  void prin()
+  {
+   	SUB *ptr;
+  	head=NULL;
+  	readfile();
+  	if(head==NULL)
+  	{
+  		printf("\n\n\t**********NO RECORDS!**********\n");
+  		return;
+	  }
+	  printf("课程编号  课程名称  课程性质  总学时  授课学时  实践或上级学时  学分  开课学期\n");
+	  for(ptr=head;ptr;ptr=ptr->next)
+	  {
+	  	printf("%5d%12s%9s%9d%9d%11d%11d%7d\n",ptr->num,ptr->name,ptr->kind,ptr->stime,ptr->ttime,ptr->etime,ptr->score,ptr->term);
+
+	  }
+	  system("pause");
+   } 
+    //下面定义浏览已选修课程模块
+   void prin1()
+   {
+   SUB *ptr;
+   head=NULL;
+  	read();
+  	if(head==NULL)
+  	{
+  		printf("\n\n\t**********NO RECORDS!**********\n");
+  		return;
+	  }
+	  printf("课程编号  课程名称  课程性质  总学时  授课学时  实践或上级学时  学分  开课学期\n");
+	  for(ptr=head;ptr;ptr=ptr->next)
+	  {
+	  	printf("%5d%12s%9s%9d%9d%11d%11d%7d\n",ptr->num,ptr->name,ptr->kind,ptr->stime,ptr->ttime,ptr->etime,ptr->score,ptr->term);
+
+	  }
+	  system("pause");
+}
+  
+	
+	//插入链表模块	
+	void *myInsert(SUB *subj)//链表插入操作
+	{
+		SUB *ptr,*ptr2;
+		ptr=subj;
+		if(head==NULL)
+		{
+			head=ptr;
+			head->next=NULL;
+		}
+		else
+		{
+			for(ptr2=head;ptr2;ptr2=ptr2->next)
+			if(ptr2->next==NULL)
+			{
+				ptr2->next=subj;
+				subj->next=NULL;
+				break;
+			}
+		}
+		return head;
+	 } 
+	 
+		 //添加模块
+	 void *insert()
+	 {
+	 	SUB *ptr,*subj;
+	 	int size=sizeof(SUB);
+	 	char ch,ch1;
+	 	while(ch!='0')
+	 	{
+	 		subj=(SUB *)malloc(size);
+	 		ptr=subj;
+	 		printf("请输入要插入的课程信息:\n");
+	 		printf("\n\t\t 请输入课程编号:");
+	 		scanf("%d",&subj->num);
+	 		printf("\n\t\t 请输入课程名称:");
+	 		scanf("%s",&subj->name);
+	 		printf("\n\t\t 请输入课程性质:");
+			 scanf("%s",&subj->kind);
+			 printf("\n\t\t 请输入总学时:");
+			 scanf("%d",&subj->stime);
+			 printf("\n\t\t 请输入授课学时:");
+			 scanf("%d",&subj->ttime);
+			 printf("\n\t\t 请输入实践或上机学时:");
+			 scanf("%d",&subj->etime);
+			 printf("\n\t\t 请输入学分:");
+			 scanf("%d",&subj->score);
+			 printf("\n\t\t 请输入开课学期:");
+			 scanf("%d",&subj->term);
+			 myInsert(subj);
+			 printf("\n添加完毕，新信息存入文件夹\n");
+			 printf("\n\n 继续插入请按回车\n");
+			 printf("\n结束添加请按 0:[ ]\b\b");
+			 ch1=getchar();
+			 ch=getchar(); 
+		 }
+		 return head;
+	  } 
+	  	  //删除模块
+	  void *del()
+	  {
+	  	SUB *p1,*p2;
+	  	char ch,ch1;
+	  	int num;
+	  	while(ch!='0')
+	  	{
+	  		printf("请输入想删除的课程编号:[   ]\b\b\b\b");
+	  		scanf("%d",&num);
+	  		if(head->num==num);
+	  		{
+	  			p2=head;
+	  			head=head->next;
+	  			free(p2);
+			  }
+			  if(head==NULL)
+			  return NULL;
+			  p1=head;
+			  p2=head->next;
+			  while(p2)
+			  {
+			  	if(p2->num==num)
+			  	{
+			  		p1->next=p2->next;
+			  		free(p2);
+				  }
+				else
+				p1=p2;
+				p2=p1->next;  
+			  }
+			  printf("\n继续删除按回车\n");
+			  printf("\n结束删除按 0:[]\b\b");
+			  ch1=getchar();
+			  ch=getchar(); 
+		  }
+		  return head;
+		  system("pause");	
+	   } 
+
+//选修课程模块
+void choose()
+{
+	SUB *p,*q;
+	int a[5];
+	int num,total=0,i=0,j;
+	printf("输入想要选修的课程编号,编号之间用空格分开\n");
+	scanf("%d",&num);
+	printf("如果确认输入完要选的编号，请输入 0:[]\n\n");
+	while(num!=0)
+	{
+		for(p=head;p;p=p->next)
+		if(p->num==num)
+		{
+			total=total+p->score;
+			a[i]=num;
+			i++;
+		}
+		scanf("%d",&num);
+	}
+	if(total<60)
+	{
+		printf("选修总学分为%d,未达到60，选修失败！",total);
+		system("pause");
+	}
+	else
+	{
+		FILE*fp;
+		fp=fopen("3.txt","w");
+		for(j=0;j<i;j++)
+		for(q=head;q;q=q->next)
+		if(q->num==a[j])
+		fprintf(fp,"%5d%12s%9s%9d%9d%11d%11d%7d\n",q->num,q->name,q->kind,q->stime,q->ttime,q->etime,q->score,q->term);
+		fclose(fp);
+		printf("\t\t\n*****选修成功！*******\n");
+		printf("\n 您选修的课程总学分为%d,课程分别为:\n",total);
+		printf("课程编号  课程名称  课程性质  总学时  授课学时  实践或上级学时  学分  开课学期\n");
+		for(j=0;j<i;j++)
+		for(q=head;q;q=q->next)
+		if(q->num==a[j])
+		printf("%5d%12s%9s%9d%9d%11d%11d%7d\n",q->num,q->name,q->kind,q->stime,q->ttime,q->etime,q->score,q->term);
+		printf("\n以上信息全部保存在'3.txt'中\n");
+		
+	}
+	system("pause");
+ } 
+ 	
+	//下面定义查询板块
+	void search()
+	{
+		int a,num;
+		int t=1;
+		char type[10],min[10];
+		SUB *ptr;
+		L1:system("cls");
+		printf("\n\n\t\t***********请选择查询方式***********\n");
+		printf("\n\t\t\t1--按课程名称查找\n");
+		printf("\n\t\t\t2--按课程性质查找\n");
+		printf("\n\t\t\t3--按学分查找\n");
+		printf("\n\t\t\t4-退出查找\n");
+		printf("\n\n\t\t************************************\n");
+		printf("\n\nChoose your numeber(1-4):[]\b\b");
+        scanf("%d",&a); 
+        switch(a)
+        {
+        	case 1:printf("输入查找课程名:");
+        	scanf("%s",min);
+        	printf("课程编号  课程名称  课程性质  总学时  授课学时  实践或上机学时  学分  开课学时\n");
+        	for(ptr=head;ptr;ptr=ptr->next)
+        	if(strcmp(min,ptr->name)==0)
+	  {
+	  	printf("%5d%12s%9s%9d%9d%11d%11d%7d\n",ptr->num,ptr->name,ptr->kind,ptr->stime,ptr->ttime,ptr->etime,ptr->score,ptr->term);
+        t=0;
+	  }
+	  if(t)
+	  printf("\t\n 未找到！\n");
+	  t=1;
+	  system("pause");
+	  goto L1;
+	  
+	  
+	  case 2:printf("请输入查找课程性质:");
+	  scanf("%s",type);
+	  printf("课程编号  课程名称  课程性质  总学时  授课学时  实践或上机学时  学分  开课学时\n");
+	  for(ptr=head;ptr;ptr=ptr->next)
+	  if(strcmp(type,ptr->kind)==0)
+	  {
+	  	printf("%5d%12s%9s%9d%9d%11d%11d%7d\n",ptr->num,ptr->name,ptr->kind,ptr->stime,ptr->ttime,ptr->etime,ptr->score,ptr->term);
+	  	t=0;
+	  	}
+	   if(t)
+	   printf("\t\n 未找到！\n");
+	   t=1;
+	   system("pause");
+	   goto L1;
+	   
+	   case 3:printf("输入要查找的课程的学分:");
+	   scanf("%d",&num);
+	   printf("课程编号  课程名称  课程性质  总学时  授课学时  实践或上机学时  学分  开课学时\n");	
+	   for(ptr=head;ptr;ptr=ptr->next)
+	  if(ptr->score==num)
+	  {
+	  	printf("%5d%12s%9s%9d%9d%11d%11d%7d\n",ptr->num,ptr->name,ptr->kind,ptr->stime,ptr->ttime,ptr->etime,ptr->score,ptr->term);
+	  	t=0;
+	  	}   
+	   if(t)
+	   printf("\n\t未找到！\n");
+	   t=1;
+	   system("pause");
+	   goto L1;
+	   
+	   case 4:break;
+}	   
+		}
+	//下面定义管理员板块
+ void Mangers()
+ {
+ 	int n,w=1,flag=0,i=3;
+ 	char s[8];
+ 	char password[7]="1";//密码为1
+	do
+	{
+		printf("\n\nEnter password:");//输入密码
+		scanf("%s",s);
+		if(!strcmp(s,password))//密码匹配验证
+		{
+			flag=1;
+			break;//输入正确 
+		 } 
+		 else
+		 {
+		 	printf("\n\nError!You only have %d times!Pleasa enter again:\n",i-1);
+		 	i--;
+		 }
+	 } 
+	 while(i>0);
+	 if(!flag)
+	 {
+	 	printf("you have already entered 3 times!");//输入密码超过3次，退出
+		exit(0);  
+	 }
+	 do
+	 {
+	 	system("cls");//清屏
+		 puts("\n\n\t\t*************管  理  员  菜  单**************\n\n");
+		  puts("\t\t\t\t1--浏览课程\n");
+		  puts("\t\t\t\t2--查询课程\n");
+		  puts("\t\t\t\t3--添加课程\n");
+		  puts("\t\t\t\t4--删除课程\n");
+		  puts("\t\t\t\t5--返回主菜单");
+		  puts("\n\n\t\t******************************************\n");
+		  printf("choose your number(1-5):[]\b\b");
+		  scanf("%d",&n);
+		  switch(n)
+		   {
+		   	case 1:prin();break;//浏览
+			case 2:search();break;//查询
+			case 3:insert();savefile();break;//添加
+			case 4:del();savefile();break;//删除
+			case 5:return;
+			default:; 
+		   }
+	 }while(w==1);
+  } 
+    
+//下面定义学生板块
+void Students()
+{
+	int n,w=1;
+	do
+	{
+		system("cls");
+		puts("\n\n\t\t**********************************\n\n");
+		puts("\t\t\t\t1--浏览所有课程\n");
+		puts("\t\t\t\t2--查询课程信息\n");
+		puts("\t\t\t\t3--选择选修课程\n");
+		puts("\t\t\t\t4--浏览我选修的课程\n");
+		puts("\t\t\t\t5--删除错选课程\n");
+		puts("\t\t\t\t6--返回");
+		puts("\n\n\t\t****************************************\n");
+		printf("choose your number(1-6):[]\b\b");
+		scanf("%d",&n);
+		switch(n)
+		{
+			case 1:prin();break;//浏览 
+			case 2:search();break;//查询 
+			case 3:choose();break;//选择 
+			case 4:prin1();break;//浏览我选修的 
+			case 5:del();savefile();break;//删除错选 
+			case 6:return;//返回 
+			default:;
+		 } 
+	}
+	while(w==1);
+ } 
+ 
+   
+  //下面编辑主页面 
+ int main()
+ {
+ 	system("color F1");
+ 	int n,w=1;
+ 	do
+ 	{
+ 		system("cls");//清除屏幕
+		 puts("\n\n\t\t****************MENU****************\n\n"); 
+		 puts("\t\t\t\t1.以管理员身份登录\n");
+		 puts("\t\t\t\t2.以学生身份登录\n");
+		 puts("\t\t\t\t3.退出");
+		 puts("\n\n\t\t***********************************\n");
+		 printf("Choose your number(1--3):[  ]\b\b");
+		 scanf("%d",&n);
+		 switch(n)
+		 {
+		 	case 1:Mangers();break;//选1，进入管理员系统
+			case 2:Students();break;//选2，进入学生系统
+			case 3:w=0;break;//选3，退出
+			default:;
+		  } 
+	 }
+	 while(w==1);
+	 return 0;
+ }
+