C language How to write the user account password to the file to implement login registration function?

Create a file that stores your user account password:

voidCreate_file () {File*FP; if(fp = fopen ("Users.txt","RB")) ==null)/*If this file does not exist*/    {        if(fp = fopen ("Users.txt","wb+"))==NULL) {Outtextxy ( -, $,"Unable to build file!"); }    }}

About file read and write:

R     Read    -only for input open a text file (the file must exist) W     write only    as output open a text file (if no file, then new) a     append    data to the end of the text file (if no file, then new) RB    Read    -only open a binary file for input WB    write    as output open a binary file ab    append    to the end of the binary file add data R+     read/write    Open a text file for read/write (file must already exist) W+ read/write     for read/write    create a new text file a+     read/write    Open a text file for read/write (read-write pointer positioned at last) RB+ read/write     open a binary filefor read/write for read/write     Create a new binary file ab for reading and writing +   Read/write    open a binary file for read-write

To create a struct body:

struct The_users   //typedef can define struct-body aliases {    char id[one by one];     Char pwd[];} Users;

The structure is used to store user account passwords.

Registered user (account password)

     voidRegisters ()//the size of the structure, write or read into 1 structure sizes at a time{users A, B;//struct the_users Rename definitionFILE *FP; FP= fopen ("Users.txt","R"); Fread (&b,sizeof(structThe_users),1, FP);//read into a struct word converts sequential blocks to BInputBox (a.id, One,"Please enter your account number");  while(1)         {                 if(strcmp (a.ID, b.id))/*if two strings are not equal*/             {                 if(!feof (FP))/*If the end of the file is not*/{fread (&b,sizeof(structThe_users),1, FP); }                 Else                      Break; }             Else{outtextxy ( -, $,"This user name already exists!");                 Fclose (FP);                  Main (); }} InputBox (A.pwd,Ten,"Please enter your password"); FP= fopen ("Users.txt","a"); Fwrite (&a,sizeof(structThe_users),1, FP); Outtextxy ( -, $,"account registration is successful!");         Fclose (FP);     Main (); } 

Login account Password:

voidInput_login () {users a,b;//define struct the_users alias FILE*FP; FP= fopen ("Users.txt","R"); Fread (&b,sizeof(structThe_users),1, FP);//read into a struct character block write BInputBox (a.id, One,"Please enter your account number"); Outtextxy (295, the, a.id);  while(1)           {              if(strcmp (a.id, b.id) = =0)//If you have this user name           {                Break; }                      Else            {               if(!feof (FP))//If the file is not finished reading{fread (&b,sizeof(structThe_users),1, FP); }                              Else               {               Outtextxy ( -, $,"This user name does not exist!");                   Fclose (FP);                                  Main (); }}} InputBox (A.pwd, -,"Please enter your password"); if(strcmp (a.pwd, b.pwd) = =0)/*if the password matches*/{fclose (FP); Outtextxy ( -, $,"Login successful, Welcome to use!");           }       Else         {   Outtextxy ( -, $,"The password is not correct!");       Main (); }       }

C language How to write the user account password to the file to implement login registration function?