学生成绩信息C程序

#include
#include
#include
#include
#define MaxSize 100
struct student{
int num;
char name [10];
int computer,math,english,sum;
float average;
};

struct student s[MaxSize];
struct student;
int count=0;

void welcome()
{
	printf ("                     +-------------------------------------+n");
	printf ("                     |      欢迎使用学生信息管理系统       |n");
	printf ("                     |                                     |n");
 	printf ("                     |                                     |n");
 	printf ("                     |                                     |n"); 
    printf ("                     +-------------------------------------+n");
}
void login() 

{ 
	
	char a[10],key[10]; 
	
	int i=0; 
	
	printf("nnnnntt请输入用户名："); 

	gets(a); 
	
	printf("nntt请输入密码："); 
	
	gets(key); 
	
	
	system("cls"); 
	
	printf("nnnnnnnntttt登录中"); 
	
	for(i=0;i<3;i++) 
		
	{ 
		
		printf("． "); 
		
		Sleep(500); 
		
	} 
	
	if(strcmp("HL",a)==0 && strcmp("0312",key)==0) 
		
	{ 
		
		system("cls"); 
		
		printf("nnnnnnnntttt登录成功,欢迎进入学生管理系统界面n"); 
		
	} 
	
	else 
		
	{ 
		
		system("cls"); 
		
		printf("nnntt您输入的用户名或密码不正确，请重新输入。n"); 
		
		login(); 
		
} }

void mainmenu()
{ 
	printf ("n");
	printf ("tttt   <学生信息管理系统>n");
	printf ("tt1.录入学生信息t"); 
	printf ("2.显示学生信息t");
	printf ("3.添加学生信息t"); 
	printf ("4.删除学生信息n");
	printf ("tt5.修改学生信息t");
	printf ("6.查找学生信息t");
	printf ("7.按总成绩降序t");
	printf ("8.按总成绩升序n");
	printf ("tt9.按学号降序t");
	printf ("10.按学号升序t");
	printf ("11.写入文件t");
	printf ("12.读出文件n");
	printf ("tt0.退出n");
	printf ("tt输入你的选择："); 
}
void new_student (struct student s[])
{
	int i,n;
	if (count==MaxSize)
	{
		printf ("The array is full! n");
		return;
	}
	printf ("输入学生人数:");
	scanf ("%d",&n);
	for (i=0;inum)
        {
        break;
        }
	}
	k=i;
	for(j=count-1;j>=k;j--)
            {
                s[j+1]=s[j];
			
            }
          printf ("再次输入学生学号:");
		scanf("%d",&s[k].num);
		printf("学生姓名：");
		scanf("%s",s[k].name);
		printf("学生数学分数：");
		scanf("%d",&s[k].math);
		printf("学生英语分数：");
		scanf("%d",&s[k].english);
		printf("学生计算机分数：");
		scanf("%d",&s[k].computer);
		count++;
	}


	
void modify (struct student *p)
{
	int num,course,score,i;
	printf ("Input the number of updated student:");
	scanf ("%d",&num);
	printf ("Choice the course: 1.math 2.english 3.computer:");
	scanf ("%d",&course);
	printf ("Input the new score:");
	scanf ("%d",&score);
	for (i=0;inum==num)
	break;
	if (imath=score;break;
		case 2:p->english=score;break;
		case 3:p->computer=score;break;
		
}	
}

void search_student(struct student s[])
{
	int i,flag,num;
	printf ("Input num:");
	scanf ("%d",&num);
	if (count==0)
	{
	printf ("count of students is zero!n");
    return;
	}
	for (i=0;is[index].num)
 		index=j;
 		t=s[index];
 		s[index]=s[i];
 		s[i]=t;
	 }
	     printf ("学号t姓名t计算机t数学t英语t总分t平均分n");
         for (i=0;is[index].sum)
 		index=j;
 		t=s[index];
 		s[index]=s[i];
 		s[i]=t;
	 }
	     printf ("学号t姓名t计算机t数学t英语t总分t平均分n");
         for (i=0;i