#define _CRT_SECURE_NO_WARNINGS

 #include <stdio.h>

 #include <stdlib.h>

 //创建结构体

 typedef struct info7k7k

 {

     char user[];

     char password[];

 }INOF,* PINOF;

 void main2x()

 {

     //以读的方式打开文件

     FILE *pfr = fopen("7k7kOK.txt", "r");

     //以写的方式打开文件

     FILE *pfw = fopen("7k7kOKwithid.txt", "w");

     //编号

     int i = ;

     //如果没到文件末尾

     while (!feof(pfr))

     {

         i++;

         //创建结构体

         INOF info1;

         //从读文件中提取字符串到info1.user和info1.password中

         fscanf(pfr, "%s%s", info1.user, info1.password);

         //格式化写入到文件中

         fprintf(pfw, "%d %s %s\n", i, info1.user, info1.password);

     }

     //关闭文件

     fclose(pfr);

     fclose(pfw);

     system("pause");

 }

 void main3x()

 {

     //int num = fprintf(stdout, "helloword%s","1234");

     //printf("\n%d", num);//fprintf返回值就是写入成功字符的个数

     FILE *pf = fopen("C:\\x.txt", "r");

     int num = fprintf(pf, "helloword%s", "");//写入失败返回-1

     printf("\n%d", num);

     system("pause");

 }

 void main()

 {

     //char str[128] = { 0 };

     //int numa;

     //int  numb;

     //int num = fscanf(stdin, "%s%d%d",str,&numa,&numb);

     ////返回值是扫描到几个数据,失败返回-1

     //printf("\n%d", num);

     FILE *pf = fopen("C:\\x.txt", "w");

     char str[] = {  };

     int numa;

     int  numb;

     int num = fscanf(pf, "%s%d%d",str,&numa,&numb);

     printf("\n%d", num);

     system("pause");

 }