Operator Overloading, Constructor, Destructor, Mutator, Facilitator methods in C++

/*This code snippet is an example of operator overloading, constructor, destructor,mutator, faclitator methods  Also it is divided in two parts, one a defintion part and another a declaration part */


#include 
using namespace std;

#include "complex1.h"

//Constructor
Complex1 :: Complex1()
{
 this->m_real = 0;
 this->m_imaginary = 0;
}
Complex1 :: Complex1(int m_real, int m_imaginary)
{
 this->m_real = m_real;
 this->m_imaginary = m_imaginary;
}

//inspector Methods

int Complex1 :: get_real() const
{
 return this->m_real;
}
int Complex1 :: get_imaginary() const
{
 return this->m_imaginary;
}

 //Mutator Methods

void Complex1 :: set_real(int m_real)
{
 this->m_real = m_real;
}
void Complex1 :: set_imaginary(int m_imaginary) 
{
 this->m_imaginary = m_imaginary;
}

 //Facilitator Methods

void Complex1 :: accept()
{
 cout << "Enter m_real and m_imaginary parts of a complex number ::";
 cin >> this->m_real >> this->m_imaginary;
}
void Complex1 :: display() const
{
 if(this->m_imaginary >= 0)
  cout << this->m_real << "+" << this->m_imaginary << "i" << endl;
 else if(this->m_imaginary < 0)
  cout << this->m_real << this->m_imaginary << "i" << endl;
}

Complex1 Complex1 :: complex_add(const Complex1& c1) const
{
 Complex1 temp;
 temp.m_real = this->m_real + c1.m_real;
 temp.m_imaginary = this->m_imaginary + c1.m_imaginary;
 return temp;
}


Complex1 Complex1 :: complex_subtract(const Complex1& c1) const
{
 Complex1 temp;
 temp.m_real = this->m_real - c1.m_real;
 temp.m_imaginary = this->m_imaginary - c1.m_imaginary;
 return temp;

}

Complex1 Complex1 :: operator+(const Complex1& c) const
{
 return complex_add(c);
}

Complex1 Complex1 :: operator-(const Complex1& c) const
{
 return complex_subtract(c);
}

Complex1 Complex1 :: operator++()
{
 this->m_real++;
 return *this;
}

Complex1 Complex1 :: operator++(int)
{
 Complex1 temp = *this;
 this->m_real++;
 return temp;
}

Complex1 Complex1 :: operator--()
{
 this->m_real--;
 return *this;
}

Complex1 Complex1 :: operator--(int)
{
 Complex1 temp = *this;
 this->m_real--;
 return temp;
 
}

bool Complex1 :: operator==(const Complex1& c)const
{
 if(this->m_real == c.m_real && this->m_imaginary == c.m_imaginary)
  return true;
 else
  return false;
}

bool Complex1 :: operator!=(const Complex1& c) const
{
 if(this->m_real != c.m_real || this->m_imaginary != c.m_imaginary)
  return true;
 else
  return false;
 
}




Complex1 :: ~Complex1()
{
 cout << "Destroying... " << endl;
}


ostream&  operator<<(ostream& out,const Complex1& c) 
{
 if(c.m_imaginary >= 0)
  out << c.m_real << "+" << c.m_imaginary << "i" << endl;
 else if(c.m_imaginary < 0)
  out << c.m_real << c.m_imaginary << "i" << endl;
 return out;
}

istream& operator>>(istream& in,Complex1& c) 
{
 in >> c.m_real >> c.m_imaginary;
 return in;
}



// Class Declaration


class Complex1
{
private:
 int m_real,m_imaginary;
public:
 //constructors
 Complex1();
 Complex1(int, int);

 //inspector Methods

 int get_real() const;
 int get_imaginary() const;

 //Mutator Methods

 void set_real(int );
 void set_imaginary(int );

 //Facilitator Methods

 void accept();
 void display() const;
 Complex1 complex_add(const Complex1& c) const;
 Complex1 complex_subtract(const Complex1& c) const;
 Complex1 operator+(const Complex1& c) const;
 Complex1 operator-(const Complex1& c) const;

 Complex1 operator++();
 Complex1 operator++(int);

 Complex1 operator--();
 Complex1 operator--(int);

 bool operator==(const Complex1&) const;
 bool operator!=(const Complex1&) const;

 friend ostream& operator<<(ostream& ,const Complex1&);
 friend istream& operator>>(istream& ,Complex1&);
 //destructor
 ~Complex1();


};

Code Snippet to implement stack in Java

class MyStack 
{
private:
 int arr[5];
 int top;

public:
 MyStack()
 {
  int i;
  for(i=0;i<5;i++)
  {
   arr[i]=0;
  }
  top=0;
 }

 void push(int val)
 {
  if(full())
   System.out.println("Stack is Full.........\n");

  this.arr[top]=val;
  this.top=this.top+1;
 }

 int pop()
 {
  if(empty())
   System.out.println("Stack is Empty.........\n");
  this.top=this.top-1;
  return arr.[top];
 }

 boolean empty()
 {
  if(this.top==0)
   return true;
  else
   return false;
 }

 boolean full()
 {
  if(this.top==5)
   return true;
  else
   return false;
 }

 
}
class DemoStack
{
 public static void main(String[] args) 
 {
  
 }
}

A program to print all possible combination of three digits(Java)

/*For example if three digits are 1,2 and 3 then all the possible combinations are 123,132,231,213,321 and 312)*/

class Combination
{
 public static int reverseNumber(int no)
 { 
  int ono=0,rev=0,rem;
  ono=no;
  while(ono!=0)
  {
   rem=ono%10;
   ono/=10;
   rev= (rev*10)+rem;
  }
  return rev;

 }

 public static void main(String[] args) 
 {
  int no,rem;
  String num=javax.swing.JOptionPane.showInputDialog("Enter Three Digit Number");
  no=Integer.parseInt(num);
  for(int j=0;j<2;j++)
  {
   for(int i=0;i<3;i++)
   {
    rem=no%10;
    no=no/10;
    no=(rem*100)+no;
    System.out.println("numbers are:"+no);
   }
   no=reverseNumber(no);
  } 

  
 }

A class to validate, increment, decrement and compare dates(Java)

class ValidateDate 
{
 int day,month,year;

 ValidateDate()
 {
  this.day=1;
  this.month=1;
  this.year=1;
 }

 ValidateDate(int d,int m,int y)
 {
  this.day=d;
  this.month=m;
  this.year=y;
 }

 void incrementByOneDay()
 {
  this.day=this.day+1;
  if(this.day > 30 )
  {
   this.day=this.day-30;
   this.month=this.month+1;
   if(this.month > 12)
   {
    this.month=this.month-12;
    this.year=this.year+1;
   }
  }
 }

 void decrementByOneDay()
 {
  this.day=this.day-1;
  if(this.day == 0 )
  {
   this.day=30;
   this.month=this.month-1;
   if(this.month == 0)
   {
    this.month=12;
    this.year=this.year-1;
   }
  }
 }

 boolean compareDates(ValidateDate d)
 {
  if(this.day==d.day && this.month==d.month && this.year==d.year)
   return true;
  else
   return false;
 }

 void displayDate()
 {
  System.out.print("Date=>"+this.day);
  System.out.print(":"+this.month);
  System.out.print(":"+this.year);
 }


 public static void main(String[] args) 
 {
  ValidateDate d1=new ValidateDate(30,12,2001); 
  d1.displayDate();
  d1.incrementByOneDay(); 
  System.out.println("After incrementing:");
  d1.displayDate();
  d1.decrementByOneDay();
  System.out.println("After decrementing:");
  d1.displayDate();

  ValidateDate d2=new ValidateDate(30,12,2001);
   if(d1.compareDates(d2))
    System.out.println("EQUAL");
   else
    System.out.println("NOT EQUAL");
   }
  }

A program find the factorial of a number using recursive functions (Java)

class Factorial 
{

 public static int factorialRec(int no)
 {
  int ans;
  if(no==1)
   return 1;
  ans=no*(factorialRec(no-1));
  return ans;
 }

 public static void main(String[] args) 
 {
  int fact,num;
  String number=javax.swing.JOptionPane.showInputDialog("Enter  Number");
  num=Integer.parseInt(number);
  fact=factorialRec(num);
  System.out.println("Factorial of number::"+fact);
 }
}

Code snippet to reverse the contents of a file (Java)

package reverse;

/* If contents of the file abc.txt are "Cricket is a religion in India", the below code will create a temp.txt file containing the output "aidnI ni noigiler a si tekcirC" */

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.FileNotFoundException;

public class Reverse {

 public static void main(String[] args) throws IOException 
 {
  FileReader fr=new FileReader("D:\\java\\workspace\\Reversefile\\src\\reverse\\abc.txt");//Enter full path of the file whose contents are to be reversed.
  
  
  BufferedReader br =new BufferedReader(fr);
  FileWriter fw=new FileWriter("temp.txt");
  String str="";
  while((str=br.readLine())!=null)
  {
   System.out.println(str);
   fw.write(new StringBuffer(str+"\n").reverse().toString());
   
  }
  fw.close();
  fr.close();
  br.close();
  
 }

}

Code snippet to read and display a file from a folder (Java)

package files;

import java.io.BufferedReader;
import java.io.IOException;

public class FileReader 
{
 public static void main(String[] args) throws IOException 
 {
  BufferedReader fr = new BufferedReader(new java.io.FileReader
  ("D:\\Amit\\JavaAssignments\\Lab3\\MyBook.java"));//Give the complete path of the file you want to read. Above is an example.

  String str;
  while((str = fr.readLine())!= null)
  {
   System.out.println(str);
  }
 }

}