Sunday, April 24, 2022
Saturday, April 16, 2022
First Set
1st Rule: if terminal, then insert terminal on set
2nd Rule: if ∈, then insert ∈ on set
3rd Rule: if non-terminal, then check the productions and insert the production elements.
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Follow Set
1st Rule: For start variable, input $
2nd Rule: if A → αBβ, then follow(B) = first(β)
3rd Rule: if A → αB, then follow(B)= follow(A)
Monday, April 4, 2022
Git Commands
git config
Usage: git config –global user.name “[name]”
Usage: git config –global user.email “[email address]”
This command sets the author name and email address respectively to be used with your commits.
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Git Config Command - Git Commands - git
git init
Usage: git init [repository name]
This command is used to start a new repository.
GitInit Command - Git Commands - git
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git clone
Usage: git clone [url]
This command is used to obtain a repository from an existing URL.
Git Clone Command - Git Commands - git
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git add
Usage: git add [file]
This command adds a file to the staging area.
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Git Add Command - Git Commands - git
Usage: git add *
This command adds one or more to the staging area.
Git Add Command - Git Commands - git
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git commit
Usage: git commit -m “[ Type in the commit message]”
This command records or snapshots the file permanently in the version history.
Git Commit Command - Git Commands - git
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Usage: git commit -a
This command commits any files you’ve added with the git add command and also commits any files you’ve changed since then.
Git Commit Command - Git Commands - git
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git diff
Usage: git diff
This command shows the file differences which are not yet staged.
Git Diff Command - Git Commands - git
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Usage: git diff –staged
This command shows the differences between the files in the staging area and the latest version present.
Git Diff Command - Git Commands - git
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Usage: git diff [first branch] [second branch]
This command shows the differences between the two branches mentioned.
Git Diff Command - Git Commands - git
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git reset
Usage: git reset [file]
This command unstages the file, but it preserves the file contents.
Git Reset Command - Git Commands - git
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Usage: git reset [commit]
This command undoes all the commits after the specified commit and preserves the changes locally.
Git Reset Command - Git Commands - git
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Usage: git reset –hard [commit] This command discards all history and goes back to the specified commit.
Git Reset Command - Git Commands - git
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git status
Usage: git status
This command lists all the files that have to be committed.
Git Status Command - Git Commands - git
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git rm
Usage: git rm [file]
This command deletes the file from your working directory and stages the deletion.
Git Rm Command - Git Commands - git
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git log
Usage: git log
This command is used to list the version history for the current branch.
Git Log Command - Git Commands - git
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Usage: git log –follow[file]
This command lists version history for a file, including the renaming of files also.
Git Log Command - Git Commands - git
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git show
Usage: git show [commit]
This command shows the metadata and content changes of the specified commit.
Git Show Command - Git Commands - git
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git tag
Usage: git tag [commitID]
This command is used to give tags to the specified commit.
Git Tag Command - Git Commands - git
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git branch
Usage: git branch
This command lists all the local branches in the current repository.
Git Branch Command - Git Commands - git
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Usage: git branch [branch name]
This command creates a new branch.
Git Branch Command - Git Commands - git
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Usage: git branch -d [branch name]
This command deletes the feature branch.
Git Branch Command - Git Commands - git
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git checkout
Usage: git checkout [branch name]
This command is used to switch from one branch to another.
Git Checkout Command - Git Commands - git
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Usage: git checkout -b [branch name]
This command creates a new branch and also switches to it.
Git Checkout Command - Git Commands - git
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git merge
Usage: git merge [branch name]
This command merges the specified branch’s history into the current branch.
Git Merge Command - Git Commands - git
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git remote
Usage: git remote add [variable name] [Remote Server Link]
This command is used to connect your local repository to the remote server.
Git Remote Command - Git Commands - git
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git push
Usage: git push [variable name] master
This command sends the committed changes of master branch to your remote repository.
Git Push Command - Git Commands - git
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Usage: git push [variable name] [branch]
This command sends the branch commits to your remote repository.
Git Push Command - Git Commands - git
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Usage: git push –all [variable name]
This command pushes all branches to your remote repository.
Git Push Command - Git Commands - git
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Usage: git push [variable name] :[branch name]
This command deletes a branch on your remote repository.
Git Push Command - Git Commands - git
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git pull
Usage: git pull [Repository Link]
This command fetches and merges changes on the remote server to your working directory.
Git Pull Command - Git Commands - git
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git stash
Usage: git stash save
This command temporarily stores all the modified tracked files.
Git Stash Command - Git Commands - git
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Usage: git stash pop
This command restores the most recently stashed files.
Git Stash Command - Git Commands - git
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Usage: git stash list
This command lists all stashed changesets.
Git Stash Command - Git Commands - git
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Usage: git stash drop
This command discards the most recently stashed changeset.
Saturday, February 26, 2022
Encapsulation
class Hello{
private int a;
public void setA(int a)
{
this.a=a;
//a=b; //if you write int b then it is appicable
}
public int getA()
{
return a;
}
}
public class Encapsulation //features :
//1.Data Hiding
//2.Flexibility
//3.Reusability
//4.Testing code
{
public static void main(String []args)
{
Hello m = new Hello();
m.setA(10);
System.out.println("Number is : "+m.getA());
}
}
Inheritance
import java.lang.*;
//Inheritance
//1.Super Class:The class whose features are inherited
//2.Sub Class: The class that inherits the other class
//3.Reusability
class Hello{
protected static int num = 0;
public final int num2 = 5;
}
class Inheritance extends Hello {
public void Hi(){
System.out.println(num);
System.out.println(num2);
}
public static void main (String [] args)
{
Inheritance obj = new Inheritance();
obj.Hi();
}
}
//Single Inheritance: one super class,one sub class
//Multilevel Inheritance:One super class will be extended by many sub class
//Hierarchical Inheritance: One super class,Many sub class
//Multiple Inheritance:One class has many super classes
//Hybrid Inheritance: Combination of single and multiple inheritance\\
//Rules:
//Multiple,Cyclic Inheritance is not permitted in java
//Private members do not get inherited
//Constructors can't be Inherited in java
//child can access parent class,parent can't access child class
//Constructors get executed beacause of super() present in the constructor
Polymorphism
/* ---------------Method Overloading-------------------
1.Methods must be same
2.Method name must be same
3.Method parameter must be different
4.Method return type may or may not be same
----------------Method Overriding-----------------
1.Must be inheritance between two classes
2.Method name must be same
3.Method parameter must be same
4.Method return type must be same
--------Constructor Overloading-------------------
1.Constructor must be of same class.
2.Constructor parameter must be different
*/
class {
public void addition(int a, int b)
{
int sum = a+b;
System.out.println(sum);
//return sum;
}
}
class Hey //method overloading
{
public void addition(double a,double b)
{
double result = a*b;
System.out.println(result);
}
}
class Hello extends Hi //method overriding
{
public void addition(int a,int b){
int sum = a-b;
//return sum;
System.out.println(sum);
}
}
public class polymorphism{
public static void main (String [] args)
{
Hello obj = new Hello();
obj.addition(4,5);
Hi scp = new Hi();
scp.addition(5,4);
Hey sc = new Hey();
sc.addition(4.5,6.5);
}
}
Abstraction
/* Rules
1.We can use object reference but we can't
create object of an abstract class.
2.Can't call constructors using new keyword but
super().this() used to call constructors.
3.An abstract class must have child class.
4.At least one regular class will inherit the
abstruct class one way or another.
5.Abstract method should be on abstract class. */
abstract class Hi{
abstract void Start();
}
class Hello extends Hi{
void Start(){
System.out.println("Hello");
}
}
class Hey extends Hello
{
void Start(){
System.out.println("Hey");
}
}
class Abstraction
{
public static void main(String [] args)
{
Hello C = new Hello();
C.Start();
Hey B = new Hey();
B.Start();
}
}
Interface
/* Rules:
1.Can take object reference
2.deafult public
3.No constructors
4.methods by default public and abstract
5.if you want to give body to any method
as interface,declare the method as static */
interface I1
{
void show();
int a= 100;
public static final int a1 =100;
}
class Interface implements I1
{
public void show()
{
System.out.println("Hello");
}
public static void main(String [] args)
{
Interface P = new Interface();
P.show();
}
}
Association
import java.util.*;
class CityClass {
private String cityName;
public String getCityName() {
return cityName;
}
public void setCityName(String cityName) {
this.cityName = cityName;
}
@Override
public String toString() {
return cityName;
}
}
class State {
private String stateName;
List<CityClass> citys;
public String getStateName() {
return stateName;
}
public void setStateName(String stateName) {
this.stateName = stateName;
}
public List<CityClass> getCities() {
return citys;
}
public void setState(List<CityClass> citys) {
this.citys = citys;
}
}
public class AssociationExample {
public static void main(String[] args) {
State state = new State();
state.setStateName("California");
CityClass city = new CityClass();
city.setCityName("Los Angeles");
CityClass city2 = new CityClass();
city2.setCityName("San Diago");
List<CityClass> empList = new ArrayList<CityClass>();
empList.add(city);
empList.add(city2);
state.setState(empList);
/*association */ System.out.println(state.getCities()+" are cities in the state "+
state.getStateName());
}
}
File Read and Write
import java.io.*;
import java.util.Scanner;
public class fileio
{
public static void main (String [] args) throws Exception
{
Scanner sc = new Scanner(System.in);
InputStreamReader isr = new InputStreamReader(System.in);
BufferedReader bfr = new BufferedReader(isr);
String s = "";
String temp;
char choice = 'y';
File file = new File("Hello.txt");
file.createNewFile();
FileWriter writer = new FileWriter(file);
System.out.println("Write Something");
while(choice=='y')
{
temp = bfr.readLine();
s = s + temp + "\n";
System.out.println("More? y for yes and n for no ");
choice = sc.next().charAt(0);
}
writer.write(s);
writer.flush();
writer.close();
FileReader reader = new FileReader(file);
BufferedReader bf1 = new BufferedReader(reader);
String a = "";
while((temp=bf1.readLine())!=null)
{
a = a+temp+"\n";
}
System.out.println(a);
reader.close();
}
}