Linux Dark Mode - Ubuntu OS, Text Editor, Facebook, Youtube, Twitter, Quora

Dark mode

Dark mode may protect your eyes. In this tutorial, I'll show you, how to turn on Dark Mode on your operating system. I'll also show you how to enable Dark Mode all social media networks i.e. Facebook, YouTube, Twitter, Quora.

Obuntu OS

You can easily enable Dark Mode in your Ubuntu Operating System.

Steps:

1. Go to Settings
2. Appearance
3. Select Window color > Dark
4. Done

Text Editor

After enabling Dark Mode on Ubuntu, there was a problem in the text editor. In the text editor, it is difficult to understand the text because of the color of the text and the background color. You can easily fix this problem for following process.

Steps:

1. Go to Text Editor
2. In top right corner, click hamburger menu (three line menu) icon 
3. Preferences
4. Select Font & Colors > Oblivion Syntax Highlight
5. Done

Facebook

Enabling Facebook Dark Mode is easy in mobile app, mobile browser and desktop or laptop web version.

Steps:

1. Go to facebook.com
2. Click on the down arrow icon in the top right corner of the menu bar
3. Display & Accessibility
4. Select Dark Mode > On
5. Done

YouTube

YouTube is the most popular video sharing platform. You can easily turn on Dark Mode on YouTube desktop version.

Steps:

1. Go to youtube.com
2. Click on the profile icon in the top right corner of the menu bar
3. Then click Appearance
4. Select Dark Theme
5. Done

Twitter

Twitter is most popular microblogging and social networking service. Turn on Dark Mode on Twitter, and protect your eyes!

Steps:

1. Go to twitter.com
2. Click the left side More option
3. Then click Display
4. Select Lights Out
5. Done

Quora

Quora is an American question-and-answer website. The team of Quora have shared the dark mode option. You can easily turn on Dark Mode on Quora desktop version.

Steps:

1. Go to quora.com
2. Click on the profile icon in the top right corner of the menu bar
3. Then click Dark Mode
4. Select Dark
5. Done

Chrome Extension

There are many dark mode chrome extension. But some time it not work properly for different color. You can search on Google for this type of chrome extension.

Project Contact Management System | Based on C Language

 TABLE OF CONTENTS

1. Introduction

2. Background

3. Requirements & Design

4. Implementation

5. Result and Evaluation

6. Conclusion

7. References

8. Source Code

1. Introduction

Contact Management System is a simple console application that is developed in C Language. This program enables to store data and manage contact information. Those are essentially databases that track all (i.e. Name, Phone Number and Email address) information and communication based on user contacts.

2. Background

Features for this application: Login, Show Contact List, Insert/Add Contact, Delete Contact, Search Contact, Security Settings, Change Username and Password, Sort Contact, Log Out, Login Again or Exit program. For this project, all of the contents based on C Language.

3. Requirements & Design

Contact Management System is console base project without graphics. It is similar to the contact manager in cell phones. This mini project use file handling and data structures. For design this project I used array, function, if...else, for loop, nested loop, switch, case, and etc. Basically, this is an easy and fundamental level mini project for learning purposes. We used simple design for this project.

4. Implementation

Describe the program code in below for understanding this project-

4.1 Set Username and Password

If user run this project for first time, Set Username and Password is mandatory option to manage contact. After set Username and Password, this is not required for next time.

Sample output:

4.2 Login to manage contacts

After set Username and Password, Login to manage contacts is another mandatory option to manage contacts.

Sample output:

4.3.1 See Contact List

See Contact List can help to show all contact.

Sample output:

4.4.2 Add Contact

Add Contact can add Name, Phone Number and Email Address in Contact list.

Sample output:

4.5.3 Delete Contact

Delete Contact can delete Name, Phone Number and Email Address in Contact list on specific position. 

Sample output:

4.5.4 Search Contact

Search Contact can search by Name or Phone Number in Contact list for easily find people. 

Sample Output:

4.5.5 Sort Contact

Sort Contact can sort by Name or Phone Number on Contact list.

Sample Output:

4.5.6 Security Setting

For this project, the user can change Username and Password by Security Setting.

Sample Output:

4.5.8 Log Out

The user can log out from all features by Log Out option.

Sample Output:

5. Result and Evaluation

After run this project, we can see many features and add Name, Phone Number and Email address as Contact Management System. Here, the data will be stored in the ContactList.txt file. If the file is deleted, the user must lost his/her all data.

6. Conclusion

The principle behind constructing a Contact Management System is to effectively retrieve and implement any information. All the information related to a particular people can be linked and archived only to be retrieved later when they are required most.

7. References

This project based on Data Structure.

Source Code

#include <stdio.h>
#include <string.h>
#include <conio.h>
#include <stdlib.h>
#include <windows.h>
 
int size = 0, i = 0, j, position, option, isFound = 0, m, n;
FILE *fp;
char search[20];
 
struct contact
{
    char name[20], phone[20], email[30], username[20], password[20];
 
} list[100], temp;
 
int fileOpenRead();
int fileOpenWrite();
int readFile();
int mainMenu();
int main();
int forgetUserPass();
 
int optionMenu()
{
    printf("\n\n1. Main Menu\n\nEnter a following option: ");
    scanf("%d", &option);
 
    system("cls");
 
    switch(option)
    {
    case 1:
        mainMenu();
        break;
 
    default:
        printf("Invalid Input for Main Menu!\n\n");
        mainMenu();
        break;
    }
}
 
int aboutAuthor()
{
    printf("Rakibul Islam\n\n");
 
    optionMenu();
    system("cls");
}
 
int contactList()
{
    printf("Contact List");
    printf("\n------------\n\n");
 
    fileOpenRead();
 
    for(j = 0; j < size; j++)
    {
        printf("Name: %s\nPhone: %s\nEmail: %s\n\n", list[j].name, list[j].phone, list[j].email);
    }
    fclose(fp);
 
    optionMenu();
}
 
int optionMenuTwo()
{
    printf("\n\n1. Contact List\n2. Main Menu\n\nEnter a following option: ");
    scanf("%d", &option);
 
    system("cls");
 
    switch(option)
    {
    case 1:
        contactList();
        break;
 
    case 2:
        mainMenu();
 
    default:
        printf("Invalid Input for Main Menu!\n\n");
        mainMenu();
        break;
    }
}
 
int addContact()
{
    readFile();
 
    printf("Add New Contact");
    printf("\n---------------\n\n");
 
    fp = fopen("ContactList.txt", "wb");
 
    printf("Enter Name: ");
    scanf("%s", list[i].name);
 
    printf("Enter Phone Number: ");
    scanf("%s", list[i].phone);
 
    printf("Enter Email: ");
    scanf("%s", list[i].email);
 
    size++;
    i++;
 
    fileOpenWrite();
    readFile();
    printf("\n\n1. Contact List\n2. Add New Contact\n3. Main Menu\n\nEnter a following option: ");
    scanf("%d", &option);
    printf("\n");
 
    system("cls");
 
    switch(option)
    {
    case 1:
        contactList();
        break;
 
    case 2:
        addContact();
        break;
 
    case 3:
        mainMenu();
        break;
 
    default:
        printf("Invalid Input for Main Menu!\n\n");
        mainMenu();
        break;
    }
}
 
int deleteContact()
{
    printf("Delete Contact");
    printf("\n--------------\n\n");
 
    readFile();
    fileOpenRead();
 
    for(j = 0; j < size; j++)
    {
        printf("%d. Name: %s\nPhone: %s\nEmail: %s\n\n", j + 1, list[j].name, list[j].phone, list[j].email);
    }
    fclose(fp);
 
    printf("Enter a position to delete: ");
    scanf("%d", &position);
 
    if(position <= j && position > 0)
    {
        fileOpenRead();
 
        fp = fopen("ContactList.txt", "wb");
 
        for(j = position; j < size; j++)
        {
            strcpy(list[j - 1].name, list[j].name);
            strcpy(list[j - 1].phone, list[j].phone);
            strcpy(list[j - 1].email, list[j].email);
        }
        size--;
        i--;
        j--;
 
        fileOpenWrite();
        readFile();
 
        system("cls");
 
        printf("Deleted!");
        optionMenuTwo();
    }
    else
    {
        system("cls");
 
        printf("Invalid Position!");
        optionMenu();
    }
}
 
int searchContact()
{
    printf("Search Contact");
    printf("\n--------------\n\n");
 
    fileOpenRead();
 
    printf("Enter Name or Number: ");
    scanf("%s", search);
    printf("\n");
 
    for(j = 0; j < size; j++)
    {
        if((strcmp(search, list[j].name) == 0))
        {
            printf("Name: %s\nPhone: %s\nEmail: %s\n\n", list[j].name, list[j].phone, list[j].email);
            isFound = 1;
        }
        else if((strcmp(search, list[j].phone) == 0))
        {
            printf("Name: %s\nPhone: %s\nEmail: %s\n\n", list[j].name, list[j].phone, list[j].email);
            isFound = 1;
        }
    }
    fclose(fp);
 
    if(isFound == 1);
    else
    {
        printf("Not Found!\n\n");
    }
    optionMenu();
}
 
int SortByName()
{
    fileOpenRead();
 
    fp = fopen("ContactList.txt", "wb");
 
    for(m = 0; m < size - 1; m++)
    {
        for(n = 0; n < size - m - 1; n++)
        {
            if(strcmp(list[n].name, list[n + 1].name) > 0)
            {
                temp = list[n];
                list[n] = list[n + 1];
                list[n + 1] = temp;
            }
        }
    }
    fileOpenWrite();
    readFile();
    printf("Sorted!");
    optionMenuTwo();
}
 
int SortByNumber()
{
 
    fileOpenRead();
    fp = fopen("ContactList.txt", "wb");
 
    for(m = 0; m < size - 1; m++)
    {
        for(n = 0; n < size - m - 1; n++)
        {
            if(strcmp(list[n].phone, list[n + 1].phone) > 0)
            {
                temp = list[n];
                list[n] = list[n + 1];
                list[n + 1] = temp;
            }
        }
    }
    fileOpenWrite();
    readFile();
    printf("Sorted!");
    optionMenuTwo();
}
 
int SortContact()
{
    printf("Sort Contact");
    printf("\n--------------\n\n");
 
    readFile();
 
    printf("1. Sort by Name\n2. Sort by Number\n3. Main Menu\n\nEnter a following option: ");
    scanf("%d", &option);
 
    system("cls");
 
    switch(option)
    {
    case 1:
        SortByName();
        break;
 
    case 2:
        SortByNumber();
        break;
 
    case 3:
        mainMenu();
        break;
 
    default:
        printf("Invalid Input for Main Menu!\n\n");
        mainMenu();
        break;
    }
}
 
int changeUsername()
{
    readFile();
 
    printf("Change Username");
    printf("\n------------\n\n");
 
    fileOpenRead();
    fp = fopen("ContactList.txt", "wb");
 
    printf("New Username: ");
    scanf("%s", list[1].username);
 
    printf("Password: ");
    scanf("%s", list[1].password);
 
    if(strcmp(list[1].password, list[0].password) == 0)
    {
        system("cls");
 
        strcpy(list[0].username, list[1].username);
 
        printf("Username changed successfully!");
        printf("\n\n");
 
        fileOpenWrite();
        fclose(fp);
        readFile();
        optionMenu();
    }
    else
    {
        fclose(fp);
        system("cls");
 
        printf("Wrong password!\n\n");
        forgetUserPass();
    }
}
 
int changePassword()
{
    readFile();
 
    printf("Change Password");
    printf("\n---------------\n\n");
 
    fileOpenRead();
 
    printf("Password: ");
    scanf("%s", list[1].password);
 
    if(strcmp(list[1].password, list[0].password) == 0)
    {
 
        printf("New Password: ");
        scanf("%s", list[2].password);
 
confirmNewPass:
 
        fp = fopen("ContactList.txt", "wb");
 
        printf("Confirm New Password: ");
        scanf("%s", list[3].password);
 
        if(strcmp(list[2].password, list[3].password) == 0)
        {
            strcpy(list[0].password, list[3].password);
 
            fileOpenWrite();
            fclose(fp);
            system("cls");
 
            printf("Password changed successfully!");
            printf("\n\n");
 
            readFile();
            optionMenu();
        }
        else
        {
            system("cls");
 
            printf("New Password and Confirm New Password are not same!");
            printf("\n\n");
 
            //printf("Password: %s\nNew Password: %s\n", list[1].password, list[2].password);
            printf("New Password: %s\n", list[2].password);
            goto confirmNewPass;
        }
    }
    else
    {
        fclose(fp);
        readFile();
        system("cls");
 
        printf("Wrong password!\n\n");
        forgetUserPass();
    }
}
 
int securitySetting()
{
    printf("Security Setting");
    printf("\n-------------------\n\n");
 
    printf("\n\n1. Change Username\n2. Change Password\n3. Main Menu\n\nEnter a following option: ");
    scanf("%d", &option);
 
    system("cls");
 
    switch(option)
    {
    case 1:
        changeUsername();
        break;
 
    case 2:
        changePassword();
        break;
 
    case 3:
        mainMenu();
        break;
 
    default:
        printf("Invalid Input for Main Menu!\n\n");
        mainMenu();
        break;
    }
 
    readFile();
 
 
}
 
int LoggedOutPage()
{
    printf("Logged Out!\n\n");
loginOption:
    printf("1. Login\n2. Exit\n\nEnter a following option: ");
    scanf("%d", &option);
 
    system("cls");
 
    switch(option)
    {
    case 1:
        main();
        break;
 
    case 2:
        printf("Exiting...\n\n");
        exit(0);
        break;
 
    default:
        printf("Invalid Input!\n\n");
        goto loginOption;
        break;
    }
}
 
int forgetUserPass()
{
    printf("Forget Username or Passwowrd");
    printf("\n---------------------------\n\n");
 
    printf("\n\n1. Show Username\n2. Show Password\n3. Main Menu\n\n\nEnter a following option: ");
    scanf("%d", &option);
 
    system("cls");
 
    switch(option)
    {
    case 1:
        printf("Username: %s", list[0].username);
        optionMenu();
        break;
 
    case 2:
        printf("Password: %s", list[0].password);
        optionMenu();
        break;
 
    case 3:
        mainMenu();
        break;
 
    default:
        system("cls");
 
        printf("Invalid Input!\n\n");
        mainMenu();
        break;
    }
}
 
int mainMenu()
{
    printf("Contact Managmenet System");
    printf("\n-------------------------\n\n\n");
    printf("1. See Contact List\n\n");
    printf("2. Add Contact\n\n");
    printf("3. Delete Contact\n\n");
    printf("4. Search Contact\n\n");
    printf("5. Sort Contact\n\n");
    printf("6. Security Setting\n\n");
    printf("7. About Author\n\n");
    printf("8. Log Out\n\n");
 
    printf("Enter a following option: ");
    scanf("%d", &option);
    printf("\n");
 
    system("cls");
    switch(option)
    {
    case 1:
        contactList();
        break;
 
    case 2:
        addContact();
        break;
 
    case 3:
        deleteContact();
        break;
 
    case 4:
        searchContact();
        break;
 
    case 5:
        SortContact();
        break;
 
    case 6:
        securitySetting();
        break;
 
    case 7:
        aboutAuthor();
        break;
 
    case 8:
        LoggedOutPage();
        break;
 
    default:
        printf("Invalid Input! Please Enter 1 to 6:\n\n");
        break;
    }
}
 
 
int main()
{
    SetConsoleTitle("Contact Managment System");
 
    //Default Password and Username.
    //strcpy(list[0].username, "0");
    //strcpy(list[0].password, "0");
 
    readFile();
    fileOpenRead();
 
    if(strcmp(list[0].username, "") == 0 && strcmp(list[0].password, "") == 0)
    {
        fp = fopen("ContactList.txt", "wb");
 
        printf("\t\t\t\tSet Username and Password\n");
        printf("\t\t\t\t------------------------\n");
 
        printf("\t\t\t\tEnter username: ");
        scanf("%s", list[0].username);
 
        printf("\n\t\t\t\tEnter password: ");
        scanf("%s", list[0].password);
        printf("\n");
 
        fileOpenWrite();
        readFile();
        fclose(fp);
 
        system("cls");
    }
    fclose(fp);
login:
    readFile();
    fileOpenRead();
 
    printf("\t\t\t\tLogin to manage contacts\n");
    printf("\t\t\t\t------------------------\n");
    printf("\t\t\t\tEnter username: ");
    scanf("%s", list[1].username);
 
    printf("\n");
    printf("\t\t\t\tEnter password: ");
    scanf("%s", list[1].password);
    printf("\n");
 
    if(strcmp(list[1].username, list[0].username) == 0 && strcmp(list[1].password, list[0].password) == 0)
    {
        fclose(fp);
 
        system("cls");
        printf("\t\t\t\tLogin successful!\n\n");
        printf("\n\n");
        readFile();
 
        while(1) //1 for infinite loop.
        {
            mainMenu();
        }
    }
    else
    {
invalid:
 
        system("cls");
 
        printf("Wrong useraname or password!\n\n");
 
        printf("1. Forget Useraname or Password\n2. Login\n\nEnter a following option: ");
        scanf("%d", &option);
 
        system("cls");
 
        switch(option)
        {
        case 1:
            printf("After few second it's automatically go Login page.\n\n");
            printf("Username: %s\nPassword: %s\n\nPlease wait...", list[0].username, list[0].password);
 
            Sleep(5000);
            system("cls");
 
            goto login;
            break;
 
        case 2:
            goto login;
            break;
 
        default:
            printf("Invalid Input!\n\n");
            goto invalid;
            break;
        }
    }
 
}
 
int fileOpenRead()
{
    fp = fopen("ContactList.txt", "rb");
 
    fread(&list, sizeof(list), 1, fp);
    fread(&size, sizeof(size), 1, fp);
    fread(&i, sizeof(i), 1, fp);
}
 
int fileOpenWrite()
{
    fwrite(&list, sizeof(list), 1, fp);
    fwrite(&size, sizeof(size), 1, fp);
    fwrite(&i, sizeof(i), 1, fp);
    fclose(fp);
}
 
int readFile()
{
    fileOpenRead();
 
    for(j = 0; j < size; j++)
    {
        list[j].name;
        list[j].phone;
        list[j].email;
    }
    fclose(fp);
}

Write a C/JAVA program to implement CRC

Implement CRC

The program will take a sequence of binary data bits, and a divider as input. And gives the resultant data with CRC as output. (Where, divider < binary data bits)

Sample Input:
Data: 10110
Divider: 1101

Sample Output:
Modified data: 10110000
Data Send: 10110101
CRC bit: 101

Sample Output

Enter data: 1001
Enter divisor: 1011

Input Data With Zero(s): 1001000

CRC Bit: 110

Modified Data: 1001110

Source Code

#include<stdio.h>
#include<stdlib.h>
 
void main()
{
    int i, j, k, l, numOfZero, dataLen;
    char divisor[100], data[100], remainder[100], divisorClone[100], dataClone[100], crc[100];
 
    printf("Enter data: ");
    scanf("%s", data);
    printf("Enter divisor: ");
    scanf("%s", divisor);
 
    for(i = 0; data[i] != '\0'; i++);
    dataLen = i;
    for(i = 0; divisor[i] != '\0'; i++);
    numOfZero = i;
 
    for(i = 0; i < numOfZero-1; i++)
    {
        data[dataLen+i] = '0';
    }
    printf("\nInput Data With Zero(s): %s\n", data);
    strcpy(dataClone, data);
 
    for(i = 0; i < dataLen; i++)
    {
        strcpy(divisorClone, divisor);
        if(data[i] < divisor[0])
        {
            for(l = 0; l < numOfZero; l++)
            {
                divisor[l] = '0';
            }
            divisor[l] = '\0';
        }
        for(j = i, k = 0; j < numOfZero+i; j++, k++)
        {
            if(data[j] == divisor[k])
            {
                remainder[j] = '0';
            }
            else
            {
                remainder[j] = '1';
            }
        }
        strcpy(divisor, divisorClone);
        remainder[j] = dataClone[j];
        remainder[j+1] = '\0';
        strcpy(data, remainder);
    }
    strcpy(data, remainder);
 
    for(i = dataLen, j = 0; i < dataLen+numOfZero; i++)
    {
        dataClone[i] = data[i];
        crc[j++] = data[i];
    }
    crc[j-1] = '\0';
    dataClone[i-1] = '\0';
 
    printf("\nCRC Bit: %s\n\nModified Data: %s\n\n", crc, dataClone);
}

Sample Output

Enter data: 10111011
Enter divisor: 1001

Input Data With Zero(s): 10111011000

CRC Bit: 110

Modified Data: 10111011110