Login Using a Text File in C

While I'm writing my book on C programming I came across with the idea to include in my book topic on File Handling in C.  The idea is to write a program using C as my programming language to store a username and password in a text file and create a login program that will ask the user to give the username and password. The program will search for the username and password that is already stored in our text file. In this example the name of the text file is users.txt. I

If the username and password are correct and can be located in the text file the program will allow the user to access the system. But if username or password is incorrect the program will not allow the user to access the system. I hope you will find my work useful.  Thank you.

I am currently accepting programming work, it projects, school and application development.

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work, computer tutorials, and web development work kindly contact me in the following email address for further details.  If you want to advertise on my website kindly contact me also in my email address also. Thank you.

My email address is the following jakerpomperada@gmail.com, jakerpomperada@aol.com, and jakerpomperada@yahoo.com.

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Here in Bacolod I also accepting computer repair, networking and Arduino Project development at a very affordable price.

My personal website is http://www.jakerpomperada.com

Sample Program Output

Program Listing

/* login.c 

 Author    : Jake Rodriguez Pomperada,MAED-IT 

 Website   : http://www.jakerpomperada.com

 Emails    : jakerpomperada@gmail.com and jakerpomperada@aol.com

 Location  : Bacolod City, Negros Occidental

 Tool      : Dev C++ Version 5.11

 Date      : January 7, 2019   3:46 PM Monday

*/

#include <stdio.h>

#include <conio.h>

#include <stdlib.h>

#include <string.h>

void get_ID_and_PASS(char fileName[30],char *id,char *pass)

{

    FILE *F = fopen(fileName,"r");

    if(F)

    {

        int count = 0;

        while(!feof(F))

        {

            char rawLine[50];

            fscanf(F,"%s",rawLine);

            if(!count++)

                strcpy(id,rawLine);

            else

                strcpy(pass,rawLine);

        }

    }else printf("Cannot open this file");

    fclose(F);

}

int main()

{

    char fileName[30] = "users.txt";

    char userID[50],userPassW[50];

    char strID[50]="\0",strPASSW[50]="\0";

    char IDpref[50] = "user_id:\0",PASSWpref[50] = "password:\0";

    get_ID_and_PASS(fileName,userID,userPassW);

    char c;

    int pos = 0;

        printf("\n\n");

        printf("\tLOGIN SECURITY SYSTEM IN C USING TEXT FILES");

        printf("\n\n");

        printf("\tEnter User Name      : ");

        scanf("%s",&strID);

        printf("\n");

        printf("\tEnter Your Password  : ");

        do {

        c = getch();

        if( isprint(c) ) 

        {

            strPASSW[ pos++ ] = c;

            printf("%c", '*');

        }

        else if( c == 9 && pos )

        {

            strPASSW[pos--] = '\0';

            printf("%s", "\b \b");

        }

    } while( c != 13 );

        strcpy(strID,strcat(IDpref,strID));

        strcpy(strPASSW,strcat(PASSWpref,strPASSW));

        if (!strcmp(strID,userID)&&!strcmp(strPASSW,userPassW))

        {

            printf("\n\n");

            printf("\tCorrect Username And Password\n");

            printf("\n\n\tWelcome to the System\n\n"); 

        }

        else

        {

           printf("\n\n");

           printf("\tInvalid Username And Password. Try Again\n\n");

         }

     printf("\n\n");

     printf("\tEND OF PROGRAM");

     printf("\n\n");

     system("pause");

}

users.txt

user_id:admin

password:Jake123!@#