Question

Write a code in C language to do following: 1. display pin input by user in **** form instead of numbers by using ncurses 2. verify the pin by comparing with already stored 2 pins in a text file 3. change text color as per user choice

WINDOWS BASED

Answer 1

//code for the problem

#include<stdio.h>
#include<conio.h>
#include<stdbool.h>
#include<windows.h>

HANDLE console_handle;                           //we will create a handle to our window

int gettextattribute(){                          
   CONSOLE_SCREEN_BUFFER_INFO buffer;           //object of console screen buffer
   GetConsoleScreenBufferInfo(console_handle,&buffer);
   return buffer.wAttributes;
}

void textcolor(int color){
   SetConsoleTextAttribute(console_handle, (gettextattribute() & 0xf0) |color);
                                               //this sets the console texr arrtribut to color  
}

void main(){
   char userid[8];                           //to make it easiar to understand i took a 8 digit user id
   printf("Enter your user id\n");
   scanf("%s",userid); //to defferentiate between different users
   char pass[30];
   int i=0,j;
   do{
       pass[i]=getch();                    //here getch() takes input till it takes
                                           //\r as input, which indicates that user hit enter.
if(pass[i]!='\r'){
printf("*");                    //we will print * corresponding to every input
}
i++;
   }while(pass[i-1]!='\r');
   pass[i-1]='\0';
   FILE *fl= fopen("abc.txt","r");           //open the file
   char data[50];
   bool flag;
   while(fgets(data,50,fl)!=NULL){           //reads file line by line
       //printf("%s",data);
       flag=false;
       for(j=0;j<8;j++){
           if(data[i]!=userid[i]){
               flag=true;                   //user id mismatch
               break;
           }  
       }
       if(!flag){
           for(j=0;j<i-1;j++){
               if(data[9+j]!=pass[j]){
                   flag=true;               //password mismatch
                   printf("\nincorrect password\n %d\n",j,i);
                   break;
               }
           }
       }
       if(!flag){
           textcolor(5);                   //to set text color
                                           //now consoles do not support inbuilt textcolor feature, so we have to create it manually
           _cprintf("\nCorrect Password\r\n");
           break;
       }
   }
}

//corresponding abc.txt file

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