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Postfix To Prefix Conversion

Here given code implementation process.

// Java program
// Postfix to Prefix Conversion

//Stack Node
class Node
{
	public String data;
	public Node next;
	public Node(String data)
	{
		this.data = data;
		this.next = null;
	}
}
class MyStack
{
	public Node top;
	public MyStack()
	{
		this.top = null;
	}
	//Count number of elements in stack 
	public int is_size()
	{
		int counter = 0;
		Node temp = this.top;
		while (temp != null)
		{
			counter++;
			temp = temp.next;
		}
		return counter;
	}
	//Add a new element in stack
	public void push(String data)
	{
		//Make a new stack node
		Node new_node = new Node(data);
		if (new_node != null)
		{
			new_node.next = top;
			top = new_node;
		
		}
		else
		{
			System.out.print("Memory overflow\n");
		}
	}
	//Add a top element in stack
	public String pop()
	{
		String temp = "";
		if (top != null)
		{
			temp = top.data;
			top = top.next;
		}
		return temp;
	}
	public boolean is_empty()
	{
		if (this.top != null)
		{
			return false;
		}
		else
		{
			return true;
		}
	}
	//Used to get top element of stack
	public String peek()
	{
		if (top != null)
		{
			return top.data;
		}
		else
		{
			return "";
		}
	}
	public void prefix(String postfix)
	{
		int size = postfix.length();
		MyStack collection = new MyStack();
		String auxiliary = "";
		for (int i = 0; i < size; ++i)
		{
			//Check whether given postfix location at [i] is an operator or not
			if (postfix.charAt(i) == '+' 
                || postfix.charAt(i) == '-' 
                || postfix.charAt(i) == '*' 
                || postfix.charAt(i) == '/' 
                || postfix.charAt(i) == '^')
			{
				//When operator exist
				//Check stack size
				if (collection.is_empty()==false)
				{
					auxiliary = collection.pop();
					auxiliary = collection.pop() + auxiliary;
					auxiliary = postfix.charAt(i) + auxiliary;
					collection.push(auxiliary);
				}
			}
			else if ((postfix.charAt(i) >= '0' 
                      && postfix.charAt(i) <= '9') 
                     || (postfix.charAt(i) >= 'a' 
                         && postfix.charAt(i) <= 'z') 
                     || (postfix.charAt(i) >= 'A' 
                         && postfix.charAt(i) <= 'Z'))
			{
				auxiliary = ""+postfix.charAt(i);
				collection.push(auxiliary);
			}
			else
			{
				System.out.print("Invalid Postfix" + postfix + "\n" + postfix.charAt(i));
				return;
			}
		}
      	System.out.print("\nPostfix : "+ postfix);
		System.out.print("\nPrefix  : "+ collection.pop());
	}
	public static void main(String[] args)
	{
		MyStack obj = new MyStack();
		String postfix = "ab+c*ef+g/+";
		obj.prefix(postfix);
	}
}

Output

Postfix : ab+c*ef+g/+
Prefix  : +*+abc/+efg

//Include header file
#include <iostream>

#include<string.h>

using namespace std;
// C++ program
// Postfix to Prefix Conversion
//Stack Node
class Node
{
	public: 
    string data;
	Node * next;
	Node(string data)
	{
		this->data = data;
		this->next = NULL;
	}
};
class MyStack
{
	public: Node * top;
	MyStack()
	{
		this->top = NULL;
	}
	//Count number of elements in stack 
	int is_size()
	{
		int counter = 0;
		Node * temp = this->top;
		while (temp != NULL)
		{
			counter++;
			temp = temp->next;
		}
		return counter;
	}
	//Add a new element in stack
	void push(string data)
	{
		//Make a new stack node
		Node * new_node = new Node(data);
		if (new_node != NULL)
		{
			new_node->next = this->top;
			this->top = new_node;
		}
		else
		{
			cout << "Memory overflow\n";
		}
	}
	//Add a top element in stack
	string pop()
	{
		string temp = "";
		if (this->top != NULL)
		{
			temp = this->top->data;
			this->top = this->top->next;
		}
		return temp;
	}
	bool is_empty()
	{
		if (this->top != NULL)
		{
			return false;
		}
		else
		{
			return true;
		}
	}
	//Used to get top element of stack
	string peek()
	{
		if (this->top != NULL)
		{
			return this->top->data;
		}
		else
		{
			return "";
		}
	}
	void prefix(string postfix)
	{
		int size = postfix.size();
		MyStack collection = MyStack();
		string auxiliary = "";
		for (int i = 0; i < size; ++i)
		{
			//Check whether given postfix location at [i] is an operator or not
			if (postfix[i] == '+' || postfix[i] == '-' || postfix[i] == '*' || postfix[i] == '/' || postfix[i] == '^')
			{
				//When operator exist
				//Check stack size
				if (collection.is_empty() == false)
				{
					auxiliary = collection.pop();
					auxiliary = collection.pop() + auxiliary;
					auxiliary = postfix[i] + auxiliary;
					collection.push(auxiliary);
				}
			}
			else if ((postfix[i] >= '0' && postfix[i] <= '9') || (postfix[i] >= 'a' && postfix[i] <= 'z') || (postfix[i] >= 'A' && postfix[i] <= 'Z'))
			{
				auxiliary = postfix[i];
				collection.push(auxiliary);
			}
			else
			{
				cout << "Invalid Postfix" << postfix << "\n" << postfix[i];
				return;
			}
		}
		cout << "\nPostfix : " << postfix;
		cout << "\nPrefix  : " << collection.pop();
	}
};
int main()
{
	MyStack obj = MyStack();
	string postfix = "ab+c*ef+g/+";
	obj.prefix(postfix);
	return 0;
}

Output

Postfix : ab+c*ef+g/+
Prefix  : +*+abc/+efg

//Include namespace system
using System;
// C# program
// Postfix to Prefix Conversion
//Stack Node
class Node
{
	public String data;
	public Node next;
	public Node(String data)
	{
		this.data = data;
		this.next = null;
	}
}
class MyStack
{
	public Node top;
	public MyStack()
	{
		this.top = null;
	}
	//Count number of elements in stack 
	public int is_size()
	{
		int counter = 0;
		Node temp = this.top;
		while (temp != null)
		{
			counter++;
			temp = temp.next;
		}
		return counter;
	}
	//Add a new element in stack
	public void push(String data)
	{
		//Make a new stack node
		Node new_node = new Node(data);
		if (new_node != null)
		{
			new_node.next = top;
			top = new_node;
		}
		else
		{
			Console.Write("Memory overflow\n");
		}
	}
	//Add a top element in stack
	public String pop()
	{
		String temp = "";
		if (top != null)
		{
			temp = top.data;
			top = top.next;
		}
		return temp;
	}
	public Boolean is_empty()
	{
		if (this.top != null)
		{
			return false;
		}
		else
		{
			return true;
		}
	}
	//Used to get top element of stack
	public String peek()
	{
		if (top != null)
		{
			return top.data;
		}
		else
		{
			return "";
		}
	}
	public void prefix(String postfix)
	{
		int size = postfix.Length;
		MyStack collection = new MyStack();
		String auxiliary = "";
		for (int i = 0; i < size; ++i)
		{
			//Check whether given postfix location at [i] is an operator or not
			if (postfix[i] == '+' || postfix[i] == '-' || postfix[i] == '*' || postfix[i] == '/' || postfix[i] == '^')
			{
				//When operator exist
				//Check stack size
				if (collection.is_empty() == false)
				{
					auxiliary = collection.pop();
					auxiliary = collection.pop() + auxiliary;
					auxiliary = postfix[i] + auxiliary;
					collection.push(auxiliary);
				}
			}
			else if ((postfix[i] >= '0' && postfix[i] <= '9') || (postfix[i] >= 'a' && postfix[i] <= 'z') || (postfix[i] >= 'A' && postfix[i] <= 'Z'))
			{
				auxiliary = "" + postfix[i];
				collection.push(auxiliary);
			}
			else
			{
				Console.Write("Invalid Postfix" + postfix + "\n" + postfix[i]);
				return;
			}
		}
		Console.Write("\nPostfix : " + postfix);
		Console.Write("\nPrefix  : " + collection.pop());
	}
	public static void Main(String[] args)
	{
		MyStack obj = new MyStack();
		String postfix = "ab+c*ef+g/+";
		obj.prefix(postfix);
	}
}

Output

Postfix : ab+c*ef+g/+
Prefix  : +*+abc/+efg

<?php
// Php program
// Postfix to Prefix Conversion
//Stack Node
class Node
{
	public $data;
	public $next;

	function __construct($data)
	{
		$this->data = $data;
		$this->next = null;
	}
}
class MyStack
{
	public $top;

	function __construct()
	{
		$this->top = null;
	}
	//Count number of elements in stack 
	public	function is_size()
	{
		$counter = 0;
		$temp = $this->top;
		while ($temp != null)
		{
			$counter++;
			$temp = $temp->next;
		}
		return $counter;
	}
	//Add a new element in stack
	public	function push($data)
	{
		//Make a new stack node
		$new_node = new Node($data);
		if ($new_node != null)
		{
			$new_node->next = $this->top;
			$this->top = $new_node;
		}
		else
		{
			echo "Memory overflow\n";
		}
	}
	//Add a top element in stack
	public	function pop()
	{
		$temp = "";
		if ($this->top != null)
		{
			$temp = $this->top->data;
			$this->top = $this->top->next;
		}
		return $temp;
	}
	public	function is_empty()
	{
		if ($this->top != null)
		{
			return false;
		}
		else
		{
			return true;
		}
	}
	//Used to get top element of stack
	public	function peek()
	{
		if ($this->top != null)
		{
			return $this->top->data;
		}
		else
		{
			return "";
		}
	}
	public	function prefix($postfix)
	{
		$size = strlen($postfix);
		$collection = new MyStack();
		$auxiliary = "";
		for ($i = 0; $i < $size; ++$i)
		{
			//Check whether given postfix location at [i] is an operator or not
			if ($postfix[$i] == '+' || $postfix[$i] == '-' || $postfix[$i] == '*' || $postfix[$i] == '/' || $postfix[$i] == '^')
			{
				//When operator exist
				//Check stack size
				if ($collection->is_empty() == false)
				{
					$auxiliary = $collection->pop();
					$auxiliary = $collection->pop() . $auxiliary;
					$auxiliary = $postfix[$i] . $auxiliary;
					$collection->push($auxiliary);
				}
			}
			else if ((ord($postfix[$i]) >= ord('0') && ord($postfix[$i]) <= ord('9')) || (ord($postfix[$i]) >= ord('a') && ord($postfix[$i]) <= ord('z')) || (ord($postfix[$i]) >= ord('A') && ord($postfix[$i]) <= ord('Z')))
			{
				$auxiliary = "". $postfix[$i];
				$collection->push($auxiliary);
			}
			else
			{
				echo "Invalid Postfix". $postfix ."\n". $postfix[$i];
				return;
			}
		}
		echo "\nPostfix : ". $postfix;
		echo "\nPrefix  : ". $collection->pop();
	}
}

function main()
{
	$obj = new MyStack();
	$postfix = "ab+c*ef+g/+";
	$obj->prefix($postfix);
}
main();

Output

Postfix : ab+c*ef+g/+
Prefix  : +*+abc/+efg

// Node Js program
// Postfix to Prefix Conversion
//Stack Node
class Node
{
	constructor(data)
	{
		this.data = data;
		this.next = null;
	}
}
class MyStack
{
	constructor()
	{
		this.top = null;
	}
	//Count number of elements in stack 
	is_size()
	{
		var counter = 0;
		var temp = this.top;
		while (temp != null)
		{
			counter++;
			temp = temp.next;
		}
		return counter;
	}
	//Add a new element in stack
	push(data)
	{
		//Make a new stack node
		var new_node = new Node(data);
		if (new_node != null)
		{
			new_node.next = this.top;
			this.top = new_node;
		}
		else
		{
			process.stdout.write("Memory overflow\n");
		}
	}
	//Add a top element in stack
	pop()
	{
		var temp = "";
		if (this.top != null)
		{
			temp = this.top.data;
			this.top = this.top.next;
		}
		return temp;
	}
	is_empty()
	{
		if (this.top != null)
		{
			return false;
		}
		else
		{
			return true;
		}
	}
	//Used to get top element of stack
	peek()
	{
		if (this.top != null)
		{
			return this.top.data;
		}
		else
		{
			return "";
		}
	}
	prefix(postfix)
	{
		var size = postfix.length;
		var collection = new MyStack();
		var auxiliary = "";
		for (var i = 0; i < size; ++i)
		{
			//Check whether given postfix location at [i] is an operator or not
			if (postfix[i] == '+' || postfix[i] == '-' || postfix[i] == '*' || postfix[i] == '/' || postfix[i] == '^')
			{
				//When operator exist
				//Check stack size
				if (collection.is_empty() == false)
				{
					auxiliary = collection.pop();
					auxiliary = collection.pop() + auxiliary;
					auxiliary = postfix[i] + auxiliary;
					collection.push(auxiliary);
				}
			}
			else if (((postfix[i]).charCodeAt(0) >= ('0').charCodeAt(0) && (postfix[i]).charCodeAt(0) <= ('9').charCodeAt(0)) || ((postfix[i]).charCodeAt(0) >= ('a').charCodeAt(0) && (postfix[i]).charCodeAt(0) <= ('z').charCodeAt(0)) || ((postfix[i]).charCodeAt(0) >= ('A').charCodeAt(0) && (postfix[i]).charCodeAt(0) <= ('Z').charCodeAt(0)))
			{
				auxiliary = postfix[i];
				collection.push(auxiliary);
			}
			else
			{
				process.stdout.write("Invalid Postfix" + postfix + "\n" + postfix[i]);
				return;
			}
		}
		process.stdout.write("\nPostfix : " + postfix);
		process.stdout.write("\nPrefix  : " + collection.pop());
	}
}

function main()
{
	var obj = new MyStack();
	var postfix = "ab+c*ef+g/+";
	obj.prefix(postfix);
}
main();

Output

Postfix : ab+c*ef+g/+
Prefix  : +*+abc/+efg

#  Python 3 program
#  Postfix to Prefix Conversion

# Stack Node
class Node :
	
	def __init__(self, data) :
		self.data = data
		self.next = None
	

class MyStack :
	
	def __init__(self) :
		self.top = None
	
	# Count number of elements in stack 
	def is_size(self) :
		counter = 0
		temp = self.top
		while (temp != None) :
			counter += 1
			temp = temp.next
		
		return counter
	
	# Add a new element in stack
	def push(self, data) :
		# Make a new stack node
		new_node = Node(data)
		if (new_node != None) :
			new_node.next = self.top
			self.top = new_node
		else :
			print("Memory overflow\n", end = "")
		
	
	# Add a top element in stack
	def pop(self) :
		temp = ""
		if (self.top != None) :
			temp = self.top.data
			self.top = self.top.next
		
		return temp
	
	def is_empty(self) :
		if (self.top != None) :
			return False
		else :
			return True
		
	
	# Used to get top element of stack
	def peek(self) :
		if (self.top != None) :
			return self.top.data
		else :
			return ""
		
	
	def prefix(self, postfix) :
		size = len(postfix)
		collection = MyStack()
		auxiliary = ""
		i = 0
		while (i < size) :
			# Check whether given postfix location at [i] is an operator or not
			if (postfix[i] == '+'
				or postfix[i] == '-'
				or postfix[i] == '*'
				or postfix[i] == '/'
				or postfix[i] == '^') :
				# When operator exist
				# Check stack size
				if (collection.is_empty() == False) :
					auxiliary = collection.pop()
					auxiliary = collection.pop() + auxiliary
					auxiliary = postfix[i] + auxiliary
					collection.push(auxiliary)
				
			
			elif((ord(postfix[i]) >= ord('0') and ord(postfix[i]) <= ord('9')) or(ord(postfix[i]) >= ord('a') and ord(postfix[i]) <= ord('z')) or(ord(postfix[i]) >= ord('A') and ord(postfix[i]) <= ord('Z'))) :
				auxiliary = ""+ postfix[i]
				collection.push(auxiliary)
			else :
				print("Invalid Postfix", postfix ,"\n", postfix[i], end = "")
				return
			
			i += 1
		
		print("\nPostfix : ", postfix, end = "")
		print("\nPrefix  : ", collection.pop(), end = "")
	

def main() :
	obj = MyStack()
	postfix = "ab+c*ef+g/+"
	obj.prefix(postfix)

if __name__ == "__main__": main()

Output

Postfix :  ab+c*ef+g/+
Prefix  :  +*+abc/+efg

#  Ruby program
#  Postfix to Prefix Conversion

# Stack Node
class Node 

	# Define the accessor and reader of class Node  
	attr_reader :data, :next
	attr_accessor :data, :next

	def initialize(data)
		self.data = data
		self.next = nil
	end
end
class MyStack 

	# Define the accessor and reader of class MyStack  
	attr_reader :top
	attr_accessor :top

	def initialize()
		self.top = nil
	end
	# Count number of elements in stack 
	def is_size()
	
		counter = 0
		temp = self.top
		while (temp != nil)
		
			counter += 1
			temp = temp.next
		end
		return counter
	end
	# Add a new element in stack
	def push(data)
	
		# Make a new stack node
		new_node = Node.new(data)
		if (new_node != nil)
		
			new_node.next = @top
			@top = new_node
		else
		
			print("Memory overflow\n")
		end
	end
	# Add a top element in stack
	def pop()
	
		temp = ""
		if (@top != nil)
		
			temp = @top.data
			@top = @top.next
		end
		return temp
	end
	def is_empty()
	
		if (self.top != nil)
		
			return false
		else
		
			return true
		end
	end
	# Used to get top element of stack
	def peek()
	
		if (@top != nil)
		
			return @top.data
		else
		
			return ""
		end
	end
	def prefix(postfix)
	
		size = postfix.length()
		collection = MyStack.new()
		auxiliary = ""
		i = 0
		while (i < size)
		
			# Check whether given postfix location at [i] is an operator or not
			if (postfix[i] == '+' || postfix[i] == '-' || postfix[i] == '*' || postfix[i] == '/' || postfix[i] == '^')
			
				# When operator exist
				# Check stack size
				if (collection.is_empty() == false)
				
					auxiliary = collection.pop()
					auxiliary = collection.pop() + auxiliary
					auxiliary = postfix[i] + auxiliary
					collection.push(auxiliary)
				end
			elsif(((postfix[i]).ord >= ('0').ord && (postfix[i]).ord <= ('9').ord) || ((postfix[i]).ord >= ('a').ord && (postfix[i]).ord <= ('z').ord) || ((postfix[i]).ord >= ('A').ord && (postfix[i]).ord <= ('Z').ord))
			
				auxiliary = ""+ postfix[i]
				collection.push(auxiliary)
			else
			
				print("Invalid Postfix", postfix ,"\n", postfix[i])
				return
			end
			i += 1
		end
		print("\nPostfix : ", postfix)
		print("\nPrefix  : ", collection.pop())
	end
end
def main()

	obj = MyStack.new()
	postfix = "ab+c*ef+g/+"
	obj.prefix(postfix)
end
main()

Output

Postfix : ab+c*ef+g/+
Prefix  : +*+abc/+efg

// Scala program
// Postfix to Prefix Conversion
//Stack Node
class Node(var data: String,
	var next: Node)
{
	def this(data: String)
	{
		this(data, null);
	}
}
class MyStack(var top: Node)
{
	def this()
	{
		this(null);
	}
	//Count number of elements in stack 
	def is_size(): Int = {
		var counter: Int = 0;
		var temp: Node = this.top;
		while (temp != null)
		{
			counter += 1;
			temp = temp.next;
		}
		return counter;
	}
	//Add a new element in stack
	def push(data: String): Unit = {
		//Make a new stack node
		var new_node: Node = new Node(data);
		if (new_node != null)
		{
			new_node.next = top;
			top = new_node;
		}
		else
		{
			print("Memory overflow\n");
		}
	}
	//Add a top element in stack
	def pop(): String = {
		var temp: String = "";
		if (top != null)
		{
			temp = top.data;
			top = top.next;
		}
		return temp;
	}
	def is_empty(): Boolean = {
		if (this.top != null)
		{
			return false;
		}
		else
		{
			return true;
		}
	}
	//Used to get top element of stack
	def peek(): String = {
		if (top != null)
		{
			return top.data;
		}
		else
		{
			return "";
		}
	}
	def prefix(postfix: String): Unit = {
		var size: Int = postfix.length();
		var collection: MyStack = new MyStack();
		var auxiliary: String = "";
		var i: Int = 0;
		while (i < size)
		{
			//Check whether given postfix location at [i] is an operator or not
			if (postfix(i) == '+' || postfix(i) == '-' || postfix(i) == '*' || postfix(i) == '/' || postfix(i) == '^')
			{
				//When operator exist
				//Check stack size
				if (collection.is_empty() == false)
				{
					auxiliary = collection.pop();
					auxiliary = collection.pop() + auxiliary;
					auxiliary = ""+postfix(i) + auxiliary;
					collection.push(auxiliary);
				}
			}
			else if ((postfix(i) >= '0' && postfix(i) <= '9') || (postfix(i) >= 'a' && postfix(i) <= 'z') || (postfix(i) >= 'A' && postfix(i) <= 'Z'))
			{
				auxiliary = "" + postfix(i);
				collection.push(auxiliary);
			}
			else
			{
				print("Invalid Postfix" + postfix + "\n" + postfix(i));
				return;
			}
			i += 1;
		}
		print("\nPostfix : " + postfix);
		print("\nPrefix  : " + collection.pop());
	}
}
object Main
{
	def main(args: Array[String]): Unit = {
		var obj: MyStack = new MyStack();
		var postfix: String = "ab+c*ef+g/+";
		obj.prefix(postfix);
	}
}

Output

Postfix : ab+c*ef+g/+
Prefix  : +*+abc/+efg

// Swift program
// Postfix to Prefix Conversion
//Stack Node
class Node
{
	var data: String;
	var next: Node? ;
	init(_ data: String)
	{
		self.data = data;
		self.next = nil;
	}
}
class MyStack
{
	var top: Node? ;
	init()
	{
		self.top = nil;
	}
	//Count number of elements in stack 
	func is_size() -> Int
	{
		var counter: Int = 0;
		var temp: Node? = self.top;
		while (temp != nil)
		{
			counter += 1;
			temp = temp!.next;
		}
		return counter;
	}
	//Add a new element in stack
	func push(_ data: String)
	{
		//Make a new stack node
		let new_node: Node? = Node(data);
		if (new_node != nil)
		{
			new_node!.next = self.top;
			self.top = new_node;
		}
		else
		{
			print("Memory overflow\n", terminator: "");
		}
	}
	//Add a top element in stack
	func pop() -> String
	{
		var temp: String = "";
		if (self.top != nil)
		{
			temp = self.top!.data;
			self.top = self.top!.next;
		}
		return temp;
	}
	func is_empty() -> Bool
	{
		if (self.top != nil)
		{
			return false;
		}
		else
		{
			return true;
		}
	}
	//Used to get top element of stack
	func peek() -> String
	{
		if (self.top != nil)
		{
			return self.top!.data;
		}
		else
		{
			return "";
		}
	}
	func prefix(_ text: String)
	{
      	let postfix = Array(text);
		let size: Int = postfix.count;
		let collection: MyStack = MyStack();
		var auxiliary: String = "";
		var i: Int = 0;
		while (i < size)
		{
			//Check whether given postfix location at [i] is an operator or not
			if (postfix[i] == "+" || postfix[i] == "-" || postfix[i] == "*" || postfix[i] == "/" || postfix[i] == "^")
			{
				//When operator exist
				//Check stack size
				if (collection.is_empty() == false)
				{
					auxiliary = collection.pop();
					auxiliary = collection.pop() + auxiliary;
					auxiliary = String(postfix[i]) + auxiliary;
					collection.push(auxiliary);
				}
			}
			else if ((postfix[i] >= "0" && postfix[i] <= "9") || (postfix[i] >= "a" && postfix[i] <= "z") || (postfix[i] >= "A" && postfix[i] <= "Z"))
			{
				auxiliary = String(postfix[i]);
				collection.push(auxiliary);
			}
			else
			{
				print("Invalid Postfix", postfix ,"\n", postfix[i], terminator: "");
				return;
			}
			i += 1;
		}
		print("\nPostfix : ", text, terminator: "");
		print("\nPrefix  : ", collection.pop(), terminator: "");
	}
}
func main()
{
	let obj: MyStack = MyStack();
	let postfix: String = "ab+c*ef+g/+";
	obj.prefix(postfix);
}
main();

Output

Postfix :  ab+c*ef+g/+
Prefix  :  +*+abc/+efg

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