通讯录的源代码（用链表实现）

#include <stdio.h>
#include <stdlib.h>  /*与malloc.h差不多*/
#include <string.h>
#define maxlen 100
strUCt persons
{ char name[10]; /*定义结构体数组用于缓存数据*/
char addr[20];
char phnum[10];
}persons[maxlen];
;
;
;
typedef struct lnode{ /*通讯录结构中结点的定义*/
char name[10]; /*姓名*/
char addr[20]; /*地址*/
char phnum[10]; /*电话*/
struct lnode *next;
}listnode,*linklist;
;
;
;
linklist head=NULL,r=NULL; /*定义头指针和尾指针*/
listnode *s,*p0,*p1,*p2,*p3,*p4,*p5,*p6,*p7;
int i;
char name1[10],ch;
char str1[20];
FILE *fp;  /*定义文件指针*/
;
;
void creat()  /*将文件的信息读入结构体数组在转存入链表中*/
{ int j;
long k;
fp=fopen("people.txt","r+t"); /*打开文件*/
if(fp!=NULL)
{for(i=1;i<maxlen;i++)
{ j=fgetc(fp);
if(j==EOF)
return;
k=i-1;
fseek(fp,k*sizeof(struct persons),0); /*读取一个人的信息*/
fread(&persons[i],sizeof(struct persons),1,fp);
s=(linklist)malloc(sizeof(listnode)); /*装存入链表中*/
strcpy(s->name,persons[i].name);
strcpy(s->addr,persons[i].addr);
strcpy(s->phnum,persons[i].phnum);
if(head==NULL)  /*用尾插法将其插入链表中*/
head=s;
else
r->next=s;
r=s;}
}
else
{ fp=fopen("people.txt","w"); /*不能打开另开辟一个文件*/
i=1;
     }
}
;
;
;
void Show() /*显示所有的信息*/
{   p1=head;
    while(p1!=NULL)
   { printf(" name:%s ",p1->name);
    printf(" addr:%s",p1->addr);
    printf(" phnum:%s",p1->phnum);
    p1=p1->next;
    }
}
;
;
;
void Delete() /*定义一个删除的函数*/
{ printf(" please input the name:");
gets(name1); /*输入要删除人的姓名*/
p4=head;
if(strcmp(p4->name,name1)==0)
     { p4=p4->next;  /*根据各种情况判定可能性*/
head=p4;
     }
else
     { while(strcmp(p4->next->name,name1)!=0)
p4=p4->next;
p5=p4->next;
p4->next=p5->next;
free(p5);
} } ;
;
;
void Find()  /*查找的函数定义*/
{ printf(" please input the name:");
p0=head;
gets(name1); /*查找人的姓名输入*/
while(strcmp(name1,p0->name)!=0&&p0!=NULL)
p0=p0->next;
if(p0==NULL)

printf(" It is not exit in the addr-book!");
else
      { printf(" name:%s ",p0->name);
printf(" addr:%s",p0->addr);
printf(" phnum:%s",p0->phnum);
        }
}
;
;
;
void Input() /*向通讯录中输入一个人的信息*/
{ s=(linklist)malloc(sizeof(listnode));
    printf(" please input the sb's meg:");
     printf(" name:");
scanf("%s",s->name);
printf(" Addr:");
scanf("%s",s->addr);
printf(" phnum:");
scanf("%s",s->phnum);
if(head==NULL)
head=s;
else
r->next=s;
r=s;
}
;
;
;
void Alter()  /*改变一个人的信息*/
{
int j;
printf(" Please input the name:");
    gets(name1); /*输入要人的姓名*/
p3=head;
while(strcmp(name1,p3->name)!=0&&p3!=NULL)
p3=p3->next;
if(p3==NULL)
printf(" It is not exit in the addr-book!");
else
     { printf(" please input the new meg!"); /*输入要改人的新信息*/
printf(" name:");
scanf("%s",name1);
strcpy(p3->name,name1);
printf(" Addr:");
scanf("%s",name1);
strcpy(p3->addr,name1);
printf(" phnum:");
scanf("%s",name1);
strcpy(p3->phnum,name1);
      }
}
;
;
;
void Save()  /*保存信息*/
{ int j;
fp=fopen("people.txt","w");
for(p2=head,j=0;p2!=NULL;j++,p2=p2->next)/*将信息装出入结构体数组在出入链表中*/
{          /*避免地址的出入，造成乱码文件*/
strcpy(persons[j].name,p2->name);
strcpy(persons[j].addr,p2->addr);
strcpy(persons[j].phnum,p2->phnum);
fwrite(&persons[j],sizeof(struct persons),1,fp);
}
}
;
;
;
void main()
{ creat();
do
    { printf(" WELCOME TO USE Pan Weifeng's Address book");/*显示提示的信息*/
printf(" Please make a choice below:");
printf(" 1.Show all the meg");
printf(" 2.Delete a piece of meg");
printf(" 3.Find a piece of meg");
printf(" 4.Insert a piece of meg");
printf(" 5.Alter a piece of meg");
printf(" 6.Save and Exit");
printf(" ");
printf(" Input Your Choice:");
ch=getche();
switch(ch)
       {   case '1': Show(); /*用单条件多选择语句实现调用与循环*/
        break;
           case '2': Delete();
        break;
           case '3': Find();
        break;

    case '4': Input();
        break;
    case '5': Alter();
        break;
    case '6': Save();
        fclose(fp);
        exit(0);
        break;
    default:
     printf(" ********************************* ");
     printf("      The num should 1-4!!!       ");
     printf(" **********************************");
     break;
}
     }while(1);
     }