利用链表实现通讯录的建立

#include <stdio.h>
#include<string.h>
#include<stdlib.h>

typedef struct lnode                              /*定义单链表*/                      
{
  char num[10];
  char name[10];
  char sex[10];
  char age[8];
  struct lnode *next;
} student;


int menu_select()                                 /*选择菜单*/
    {
    char c;
     do{ 
        system("cls"); 
        printf("\t\t *****学生通讯录***** \n");                               
        printf("\t\t┌───────——┐\n");                   
        printf("\t\t│ 1. 创建通讯录    │\n"); 
        printf("\t\t│ 2. 显示通讯录    │\n"); 
        printf("\t\t│ 3. 删除通讯录    │\n"); 
        printf("\t\t│ 4. 插入通讯录    │\n"); 
        printf("\t\t│ 5. 查询#按姓名   │\n");
                printf("\t\t│ 6. 通讯录信息更改│\n");
                printf("\t\t│ 7. 写入文本保存  │\n");
        printf("\t\t│ 8. 从文本中读取  │\n");
        printf("\t\t│ 0. 退出程序      │\n"); 
        printf("\t\t└───────——┘\n"); 
        printf("\t\t请您选择(0-8):"); 
        c=getchar();
        }
        while(c<'0'&&c>'8');
        return(c-'0'); 
    } 


void initlist(student *&l)                               /*初始化链表*/
{
l=(student *)malloc(sizeof(student));
l->next=NULL;
}



void createlistf(student *&l)                             /*创建通讯录*/
{ 
 student *r,*s;char sign;
 l=(student *)malloc(sizeof(student));
 r=l;
while(sign!='n'&&sign!='N')
{
s=(student *)malloc(sizeof(student));
printf("学号：");
scanf("%s",&(s->num));
printf("姓名：");
scanf("%s",&(s->name));
printf("性别：");
scanf("%s",&(s->sex));
printf("年龄:");
scanf("%s",&(s->age));
r->next=s;
r=s;
r->next=NULL;
printf("是否继续添加记录（Y/N）\n");
scanf("%s",&sign);

}
//r->next=NULL;
}




void displist(student *l)                                   /*显示通讯录*/
{student *p=l->next;int i;i=1;
while (p!=NULL)
{
    printf("学号：%10s\n",p->num);
    printf("姓名：%10s\n",p->name);
    printf("性别：%10s\n",p->sex);
    printf("年龄：%10s\n",p->age);
    printf("------第%d条记录-----\n",i);
    p=p->next;
    i++;
}
printf("\n");
}



void listdelete(student *&l,char *elem)                      /*删除某个信息从通讯录中*/
{

student *p=l;
student *q=p->next;
while(strcmp(elem,q->name)!=0)
{
p=q;
q=q->next;
if(q==NULL)
printf("没有此人信息，无法删除");
break;
}
if(q!=NULL)
p->next=q->next;
//else
//printf("没有此人信息，无法删除！");
}


void listinsert(student *&l,char *elem)                     /*插入信息到通讯录中*/ 
{
student *p=l->next;student *s=l;student *q;q=p;
while(p!=NULL)
{
    q=p;
    p=p->next;

}
if(p==NULL)
{
s=(student *)malloc(sizeof(student));
printf("学号：");
scanf("%s",&(s->num));
printf("姓名：");
scanf("%s",&(s->name));
printf("性别：");
scanf("%s",&(s->sex));
printf("年龄:");
scanf("%s",&(s->age));
//s->next=q->next;
q->next=s;
s->next=NULL;
}
else
printf("插入失常！");
}






void listlocate(student *&l,char *elem)                        /*按学生姓名查找某个记录*/
{
student *p=l->next; //student *s=l;

while(p!=NULL && strcmp(p->name,elem)!=0)
{
p=p->next;
}
if(p==NULL)
printf("没有此人记录");
else
printf("学号=%s,姓名=%s,性别=%s,年龄=%s",p->num,p->name,p->age,p->sex);
printf("\n");
}


void listchange(student *&l,char *elem)                        /*按学生学号修改记录*/
{
student *p=l->next; student *s;
while(p!=NULL && strcmp(p->num,elem)!=0)
p=p->next;
if(p==NULL)
printf("没有此学号学生的记录");
else
{
s=(student *)malloc(sizeof(student));
printf("学号：");
scanf("%s",&(s->num));
printf("姓名：");
scanf("%s",&(s->name));
printf("性别：");
scanf("%s",&(s->sex));
printf("年龄:");
scanf("%s",&(s->age));
strcpy(p->num,s->num);strcpy(p->name,s->name);strcpy(p->sex,s->sex);strcpy(p->age,s->age);
printf("新纪录修改为:\n");
printf("学号=%s,姓名=%s,性别=%s,年龄=%s",p->num,p->name,p->age,p->sex);
}
}



void writetotext(student *&l)                                       /*写入文本*/
{
student *p=l->next; 
FILE *fp;
char filename[20];
printf("\t保存到文件\n");
printf("\t请输入所保存的文件名:");
scanf("\t%s",filename);
if((fp=fopen(filename,"w"))==NULL)
{
   printf("\t无法打开文件\n");
   system("pause");
   return;
}
fprintf(fp,"***********通讯录************\n");
fprintf(fp,"学号   姓名    性别     年龄 \n");
while(p!=NULL)
{
fprintf(fp,"%s\t%s\t%s\t%s\t\n",p->num,p->name,p->sex,p->age);
p=p->next;
}
fclose(fp);
printf("保存成功!\n");
}






int readfromtext(student *&l)                                      /*从文本中读取*/
{
FILE *fp;
char ch;
char filename[20];
printf("\t打开的文件\n");
scanf("\t%s",filename);
fp=fopen(filename,"rb");
if(fp==NULL)
{
printf("open file error\n");
return 0;
}
while(!feof(fp))
{
ch=fgetc(fp);
printf("%c",ch);
}

fclose(fp);
}




int main()                                    /*主函数*/
{  
    
char e[80]="yangbing";
student *s;
initlist(s);
for(;;)
{
switch(menu_select())
{
 
case 1:
createlistf(s);
system("pause");
break;

case 2:
displist(s);
system("pause");
break;

case 3:
printf("输入要删除的姓名：\n");
printf("姓名：");
scanf("%s",e);
listdelete(s,e);
break;


case 4:
printf("输入要插入的信息：\n");
listinsert(s,e);
break;

case 5:
printf("输入要查询人的姓名：\n");
scanf("%s",e); 
listlocate(s,e);
system("pause");
break;

case 6:
printf("输入要修改人的学号：\n");
scanf("%s",e);
listchange(s,e);
system("pause");
break;

case 7:
writetotext(s);
system("pause");
break;

case 8:
readfromtext(s);
system("pause");
break;

case 0:                                                    /*退出程序*/
exit(0);
break;
}
}
return 1;}