C语言实现链表与文件存取的示例代码

int main(void)
{
    char filename[50];
    printf("How many ?: ");
    scanf("%d", &n);		
    printf("please input filename: ");
    scanf("%s", filename);	
    Create();       //调用函数建立链表
    save(filename); //调用函数存到文件
    free(phead);//释放phead内存
    show(filename); //调用函数输出文件
    system("pause");
    return 0;
}

typedef struct stu
{
    char name[20];
    char adr[20];
    int tel;
    struct stu* pnext;
} stu;
int n;	//n存着信息条数
stu* phead=NULL;//phead为链表首地址
 
void Create()          //建立链表
{
    stu *pend,*pnew;//尾节点，新节点
    pend=phead =(stu*)malloc(sizeof(stu));//分配内存给首节点
    printf("please first input Name, Adress and telephone:\n");
    for(int i=0;i<n;i++)
    {
        pnew=(stu*)malloc(sizeof(stu));  //分配新节点
        pend->pnext=pnew;   //原来的尾节点指向新节点
        pnew->pnext=NULL;  	//新节点的指针为NULL
        printf("NO.%d: ",i+1);
        scanf("%s", pend->name);
        scanf("%s", pend->adr);
        scanf("%d",&pend->tel);
        pend=pnew;  //赋值后指向尾节点
    }
    pnew=pnew->pnext;//指向NULL
    free(pnew);      //释放pnew内存
}

void save(char *filename)
{
    FILE *w;//文件指针
    if ((w = fopen(filename, "wb")) == NULL){   
        printf("cannot open file\n");
        exit(1);
    }
    for (int i = 0; i < n; i++)  //链表数据循环输入到文件内
    {
         fprintf(w,"%s ",phead->name);
         fprintf(w,"%s ",phead->adr);
         fprintf(w,"%d", phead->tel);
         fprintf(w,"%s","\r\n");//换行
         phead=phead->pnext;//指向下一个节点
    }
    fclose(w);	//关闭文件
}

void show(char *filename)		//输出文件
{
    FILE *fp;//文件指针
    stu info[100];  //负责存放文件中的数据，然后输出
    if ((fp = fopen(filename, "rb")) == NULL){   
        printf("cannot open file\n");
        exit(1);
    }
    for (int i = 0; i < n; i++)
    {
        fscanf(fp,"%s",&(info[i].name));//输出数据到数组
        fscanf(fp,"%s",&(info[i].adr));
        fscanf(fp,"%d",&(info[i].tel));
        printf("%10s%15s%15d\n", info[i].name,
        	info[i].adr, info[i].tel); //输出数据到屏幕
    }
    fclose(fp); //关闭文件
}        

#include<stdio.h>
#include<stdlib.h>
#include<process.h>
typedef struct stu
{
    char name[20];
    char adr[20];
    int tel;
    struct stu* pnext;
} stu;
int n;	//n存着信息条数
stu* phead=NULL;//phead为链表首地址
 
void Create()
{
    stu *pend,*pnew;//尾节点，新节点
    pend=phead =(stu*)malloc(sizeof(stu));//分配内存给首节点
    printf("please first input Name, Adress and telephone:\n");
    for (int i = 0; i < n; i++)
    {
        pnew=(stu*)malloc(sizeof(stu));  //分配新节点
        pend->pnext=pnew;   //原来的尾节点指向新节点
        pnew->pnext=NULL;   //新节点的指针为NULL
        printf("NO.%d: ",i+1);
        scanf("%s", pend->name);//输入数据存到链表中
        scanf("%s", pend->adr);
        scanf("%d",&pend->tel);
        pend=pnew;  //赋值后指向尾节点
    }
    pnew=pnew->pnext;//指向NULL
    free(pnew);      //释放pnew内存
}
void save(char *filename)
{
    FILE *w;//文件指针
    if ((w = fopen(filename, "wb")) == NULL){   
        printf("cannot open file\n");
        exit(1);
    }
    for (int i = 0; i < n; i++)  //链表数据循环输入到文件里
    {
         fprintf(w,"%s ",phead->name);//数据存入到文件
         fprintf(w,"%s ",phead->adr);
         fprintf(w,"%d", phead->tel);
         fprintf(w,"%s","\r\n");//换行
         phead=phead->pnext;//指向下一个节点
    }
    fclose(w);	//关闭文件
}
void show(char *filename)
{
    FILE *fp;//文件指针
    stu info[100];  //负责存放文件中的数据，然后输出
    if ((fp = fopen(filename, "rb")) == NULL){   
        printf("cannot open file\n");
        exit(1);
    }
    for (int i = 0; i < n; i++)
    {
        fscanf(fp,"%s",&(info[i].name));//输出数据到数组
        fscanf(fp,"%s",&(info[i].adr));
        fscanf(fp,"%d",&(info[i].tel));
        printf("%10s%15s%15d\n", info[i].name, 
        	info[i].adr, info[i].tel);//输出数据到屏幕
    }
    fclose(fp);
}
 
int main(void)
{
    char filename[50];
    printf("How many ?:\n");
    scanf("%d", &n);		
    printf("please input filename: ");
    scanf("%s", filename); 
    Create();       //调用函数建立链表
    save(filename); //调用函数存到文件
    free(phead);//释放phead内存
    show(filename); //调用函数输出文件
    system("pause");
    return 0;
}