1.cpp

学生管理系统

// 1.cpp : Defines the entry point for the console application.
//



#include "stdafx.h"
#include <stdlib.h>
#include <string.h>
//LLIST


typedef struct Student_Score{
	char Number[12];
	char Name[16];
    int Course_Score[3];
}*student;

#define Elem  student 



typedef struct LLIST{
	Elem data;
	struct LLIST *next;
}*LList;


void IninList(LList &L){//构造空链表L
	L = NULL;
}


void DestroyList(LList &L){//销毁链表L
	LList tmp = NULL;
	while(L != NULL){
		tmp = L;
		L = L->next;
		free(tmp);
	}
}/**/
/*

void ClearList(LList &L){//重置链表L
	DestroyList(L);
}

bool ListEmpty(LList L){//链表L判空
	if(L == NULL) return true;
	else return false;

}
*/
int ListLength(LList L){//返回链表L长度
	int i = 0;
	LList tmp = L;
	while(tmp != NULL){
		tmp = tmp->next;
		i++;
	}
	return i;
}

bool GetElem(LList L, int i,Elem &e){//返回链表L中第i个元素，并赋值到e
	int count = 0;
	LList tmp = L;
	while(tmp != NULL){
		if(count == i){
			e = tmp->data;
			return true;
		}
		tmp = tmp->next;
		count++;
	}
	return false;
}

void ListInsert(LList &L,Elem e){//将元素e插入链表L中的第i个元素之后
	LList node = (LList)malloc(sizeof( LLIST));
	node->data = e;
	node->next = NULL;

	
	if(L == NULL){
		
		L = node;
	}
	else{
	
			LList tmp = L;

			while(tmp->next != NULL) tmp = tmp->next;
	
			node->next = tmp->next;
			tmp->next = node;

	}
}


bool ListDelete(LList &L,int i,Elem &e){//删除链表L中第i个元素，并将其值返回到e

	LList tmp = L;
	if(L != NULL){
		if(i == 0){
		
			L = L->next;
			e = tmp->data;
			free(tmp);

			return true;
		}
		else{
			int count = 1;
			while(tmp->next->next != NULL && i != count) {tmp = tmp->next;count++;}
			//此时tmp的值为第i-1个元素的地址值或为倒数第二个元素的地址值
			if(i >= count){
				LList t = tmp->next;
				e = t->data;
				tmp->next = t->next;
				free(t);
				return true;
			}
			
		}
	}
	return false;
}





/**/



bool check(char *a,const char *b){//
    for(;*a&&*b;a++,b++){
	if(*a!=*b)return false;
	}
	if(*a||*b)return false;
    return true;
}



bool Query(LList &L,char *key,int &count){
	if(!L)return false;
	LList l=L;
	count=0;
	if(check(l->data->Number,key) || check(l->data->Name,key))return true;
	else l=l->next;
    count++;
	while(l && !( check(l->data->Number,key) || check(l->data->Name,key) ) ){
	l=l->next;
	count++;
	}
	if(!l)return false;
	else return true;
}



bool Change(char *c,int &n){
 int sum=0;
 char *s;
 s=c;


 if( !s || *s<47 || *s>57)return false;
  for(sum=*s-48;*(++s)!=0;)
  {
	if( *s>47 && *s<58)
	{
	   sum*=10;
       sum+=*s-48;
	}
	else return false;
  }
  n = sum;
  return true;

}



void read(LList &L)
{
     FILE *fp;
     int i;
	 char infile[16];
	 LList &l=L;
		 
		 scanf("%s",&infile);
	     
		 if( !(fp=fopen(infile,"r")) ){printf("无法打开该文件\n");return;}

     student tmp=(student)malloc(sizeof(Student_Score));
     for(i=0;!feof(fp);i++)
	 { 	
	  fscanf(fp,"%s %s %d %d %d\n",tmp->Number,tmp->Name,&tmp->Course_Score[0],&tmp->Course_Score[1],&tmp->Course_Score[2]);
        
		ListInsert(l,tmp);  
		sprintf(tmp->Number,"%d",ListLength(l));
		tmp=(student)malloc(sizeof(Student_Score));
	 }
	 fclose(fp);
	 printf("已从%s文件中读入%d行学生成绩信息内容写入\n",infile,i);
	


}

void write(LList L){
   FILE *fp;
   int i,t=0;
   char outfile[16];
   LList l=L; 
	   
	   scanf("%s",&outfile);
	   if( !(fp=fopen(outfile,"w+")) ){printf("无法打开该文件\n");return;}

   
   student tmp=(student)malloc(sizeof(Student_Score));

   for(i=ListLength(l);t<i;t++){
       GetElem(l,t,tmp);
	   fprintf(fp,"%s %s %4d %4d %4d\n",&tmp->Number,&tmp->Name,tmp->Course_Score[0],tmp->Course_Score[1],tmp->Course_Score[2]);
   }

   fclose(fp);
   printf("已将%d行学生成绩信息内容写入%s文件中\n",i,outfile);
   
}



void PrintStuInfo(student tmp){
    if(tmp)
	printf("%s\t%s\t%d\t%d\t%d\n",tmp->Number,tmp->Name,tmp->Course_Score[0],tmp->Course_Score[1],tmp->Course_Score[2]);
    else printf("错误!\n");
}

void StudentInfoTraverse(LList &L){//遍历学生成绩链表的内容
  LList l=L;
  if(!l){printf("当前学生成绩系统为空!\n");return;}
  printf("以下为学生成绩信息\nNumber  Name	Math  English  Computer\n");
  while(l)
  {
	  printf("%s\t%s\t%d\t%d\t%d\n",l->data->Number,l->data->Name,l->data->Course_Score[0],l->data->Course_Score[1],l->data->Course_Score[2]);
      l=l->next;
  }
}




void AddStudent(LList &L){//插入学生成绩，输入信息包括姓名、三科成绩


 char tmp[16];
 int count=0,i=0,t;
 student st=(student)malloc(sizeof(Student_Score));
 
   for( i=0;;i++){
       
	   scanf("%s",tmp);
	   if(check(tmp,"end"))break;
 

	   
	   if(!i && Query(L,tmp,t)){printf("该学生信息已经存在！\n");i=-1;flushall();continue;}
       if(!i){
		  strcpy(st->Name,tmp);
		 
		  sprintf(st->Number,"%d",++count);
	      int k=0;
	      while(k<3)
		  {
			  st->Course_Score[k]=0;//所有成绩清0
			  k++;
		  }
       }
       if(i) {
		   if( !Change(tmp,st->Course_Score[i-1]) || st->Course_Score[i-1]>100 ){printf("输入成绩不正确!\n");i=-1;continue;} 
	   }

       if(i==3){ListInsert(L,st);break;}
   }
   if(i==1)ListInsert(L,st);
   printf("已插入第个%d学生成绩信息\n",ListLength(L));
}





void DeleteStudent(LList &L){
   
	LList &l=L;
	char Input[16];
	int i;

		if(!l){printf("当前信息为空\n");return;}

		scanf("%s",Input);
        
		if(Query(l,Input,i)){
			printf("你要删除的信息为第%d行学生的信息\n",i+1);
			student tmp=(student)malloc(sizeof(Student_Score));
			GetElem(l,i,tmp);
			PrintStuInfo(tmp);
            ListDelete(l,i,tmp);
		}
		else printf("当前并没有包含%s的信息\n",Input);

}



void ChangeStudent(LList &L){
	LList l=L;
	char Input[16],change[16];
	int i;
	if(!l){printf("当前信息为空\n");return;}

		scanf("%s",Input);
        
		if(Query(l,Input,i)){

			student tmp=(student)malloc(sizeof(Student_Score));
			GetElem(l,i,tmp);
            printf("要修改的数据内容为  ");
			PrintStuInfo(tmp);
			scanf("%s",change);
			char  *Score[]={"Name","Math","English","Computer",""};
			int t=0;

			for(;Score[t]!="";t++){
				if(check(change,Score[t]))break;
			}

            if(t==4){printf("该行并没有包含%s项数据，可修改的数据项为Number  Name  Math  English  Computer",change);}
			
			scanf("%s",change);

			if(t)Change(change,tmp->Course_Score[t-1]);
			else strcpy(tmp->Name,change);
							  
		}
		else printf("当前并没有包含%s的信息\n",Input);
       
}





bool AverageScore(LList &L,float average[]){
  
  if(!L){printf("当前并无学生信息\n");return false;}
  LList l=L;
  int i;
  for(i=0;i<3;i++)average[i]=0; 
  
  for(;l;l=l->next){
	  for(i=0;i<3;i++){
	    average[i]+=l->data->Course_Score[i];
	  }
  }
  l=L;
  for(i=0;i<3;i++)average[i]/=ListLength(l);
  return true;

}


int main(int argc, char* argv[])
{

    char *order[]={"query","add","change","delete","average","read","write","destroy","print","exit",""},Input[16],keyword[16];
	int i;
	printf("请输入以下指令集中的指令操作学生成绩系统.\n");
	printf("指令集包括query(查询)、add(添加学生信息)、change(修改学生成绩)、\ndelete(删除学生信息)、average(求各科全班平均分)、");
	printf("read(读取文件信息)、\nwrite(将信息写入文件)、destroy(销毁数据)、exit(退出)、print(打印当前系统信息)\n");
    printf("指令格式：query keyword,delete keyword,read file,write file,average,exit,print\n\t  add Name Math English Computer,change keyword value\n");
	printf("          其中keyword为查询、修改、删除的关键字,可以为学生编号或者学生姓名,\n");
	printf("          而value值为Name,Math,English,Computer中的任意一个\n	 (注：学生编号由系统生成)\n");
	//printf("\n	 ");
   
    LList L;
    IninList(L);
	
	while(1){
	   if(!L)printf("	当前并无学生信息\n	建议插入学生数据,或者可输入exit退出\n");
	   scanf("%s",Input);
	   for(i=0;order[i]!="";i++){if(check(Input,order[i]))break;}
	  
	    switch(i){
		case 0: scanf("%s",keyword);
			    if(!Query(L,keyword,i))
				printf("查询失败。\n无法找到关键字为%s字段的信息，keyword只包含学生编号或者学生姓名\n",keyword);
			    else {
				printf("查询结果\n");
				student tmp=(student)malloc(sizeof(Student_Score));
				GetElem(L,i,tmp);
				PrintStuInfo(tmp);
				}
		    	break;
			
		case 1:AddStudent(L);break;
		case 2:ChangeStudent(L);break;
		case 3:DeleteStudent(L);break;
		case 4:float average[3];
			   if(AverageScore(L,average)){
			       printf("averageScore Math English Computer\n");
			       printf("     %f   %f   %f \n",average[0],average[1],average[2]);
			   }
			   break;
		case 5:read(L);break;
		case 6:write(L);break;
		case 7:DestroyList(L);IninList(L);break;
		case 8:StudentInfoTraverse(L);break;
		case 9:return 0;
		default:printf("输入指令错误！\n");break;
			
	   }
	   flushall();//清空输入的缓存


	}
	return 0;
}