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Prefix to infix conversion

Here given code implementation process.

// Java program
// Prefix to infix 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;
	}
	//Check two operands exist or not
	public boolean is_two_operands()
	{
		int counter = 0;
		Node temp = this.top;
		while (temp != null && counter < 2)
		{
			counter++;
			temp = temp.next;
		}
		return counter == 2;
	}
	//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 "";
		}
	}
	//Converting the given prefix expression to infix expression
	public void infix_conversion(String prefix)
	{
		//Get the size
		int size = prefix.length();
		//Create stack object
		MyStack collection = new MyStack();
		//Some useful variables which is using of to storing current result
		String auxiliary = "";
		String op1 = "";
		String op2 = "";
		boolean is_valid = true;
		for (int i = size - 1; i >= 0; i--)
		{
			//Check whether given prefix location at [i] is an operator or not
			if (prefix.charAt(i) == '+' || prefix.charAt(i) == '-' || prefix.charAt(i) == '*' || prefix.charAt(i) == '/' || prefix.charAt(i) == '^' || prefix.charAt(i) == '%')
			{
				// When operator exist
				// Check that two operands exist or not
				if (collection.is_two_operands() == true)
				{
					op1 = collection.pop();
					op2 = collection.pop();
					auxiliary = "(" + op1 + prefix.charAt(i) + op2 + ")";
					collection.push(auxiliary);
				}
				else
				{
					is_valid = false;
				}
			}
			else if ((prefix.charAt(i) >= '0' && prefix.charAt(i) <= '9') || (prefix.charAt(i) >= 'a' && prefix.charAt(i) <= 'z') || (prefix.charAt(i) >= 'A' && prefix.charAt(i) <= 'Z'))
			{
				auxiliary = "" + prefix.charAt(i);
				collection.push(auxiliary);
			}
			else
			{
				is_valid = false;
			}
		}
		if (is_valid == false)
		{
			System.out.print("Invalid Prefix : " + prefix);
		}
		else
		{
			System.out.print("\n Prefix : " + prefix);
			System.out.print("\n Infix  : " + collection.pop());
		}
	}
	public static void main(String[] args)
	{
		MyStack obj = new MyStack();
		String prefix = "+*ab^cd";
		obj.infix_conversion(prefix);
		prefix = "-+*^%adcex*y^ab";
		obj.infix_conversion(prefix);
	}
}

Output

 Prefix : +*ab^cd
 Infix  : ((a*b)+(c^d))
 Prefix : -+*^%adcex*y^ab
 Infix  : (((((a%d)^c)*e)+x)-(y*(a^b)))

//Include header file
#include <iostream>

#include<string.h>

using namespace std;
// C++ program
// Prefix to infix 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;
	}
	//Check two operands exist or not
	bool is_two_operands()
	{
		int counter = 0;
		Node * temp = this->top;
		while (temp != NULL && counter < 2)
		{
			counter++;
			temp = temp->next;
		}
		return counter == 2;
	}
	//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 "";
		}
	}
	//Converting the given prefix expression to infix expression
	void infix_conversion(string prefix)
	{
		//Get the size
		int size = prefix.size();
		//Create stack object
		MyStack collection = MyStack();
		//Some useful variables which is using of to storing current result
		string auxiliary = "";
		string op1 = "";
		string op2 = "";
		bool is_valid = true;
		for (int i = size - 1; i >= 0; i--)
		{
			//Check whether given prefix location at [i] is an operator or not
			if (prefix[i] == '+' || prefix[i] == '-' || prefix[i] == '*' || prefix[i] == '/' || prefix[i] == '^' || prefix[i] == '%')
			{
				// When operator exist
				// Check that two operands exist or not
				if (collection.is_two_operands() == true)
				{
					op1 = collection.pop();
					op2 = collection.pop();
					auxiliary = "(" + op1 + prefix[i] + op2 + ")";
					collection.push(auxiliary);
				}
				else
				{
					is_valid = false;
				}
			}
			else if ((prefix[i] >= '0' && prefix[i] <= '9') || (prefix[i] >= 'a' && prefix[i] <= 'z') || (prefix[i] >= 'A' && prefix[i] <= 'Z'))
			{
				auxiliary = prefix[i];
				collection.push(auxiliary);
			}
			else
			{
				is_valid = false;
			}
		}
		if (is_valid == false)
		{
			cout << "Invalid Prefix : " << prefix;
		}
		else
		{
			cout << "\n Prefix : " << prefix;
			cout << "\n Infix  : " << collection.pop();
		}
	}
};
int main()
{
	MyStack obj = MyStack();
	string prefix = "+*ab^cd";
	obj.infix_conversion(prefix);
	prefix = "-+*^%adcex*y^ab";
	obj.infix_conversion(prefix);
	return 0;
}

Output

 Prefix : +*ab^cd
 Infix  : ((a*b)+(c^d))
 Prefix : -+*^%adcex*y^ab
 Infix  : (((((a%d)^c)*e)+x)-(y*(a^b)))

//Include namespace system
using System;
// C# program
// Prefix to infix 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;
	}
	//Check two operands exist or not
	public Boolean is_two_operands()
	{
		int counter = 0;
		Node temp = this.top;
		while (temp != null && counter < 2)
		{
			counter++;
			temp = temp.next;
		}
		return counter == 2;
	}
	//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 "";
		}
	}
	//Converting the given prefix expression to infix expression
	public void infix_conversion(String prefix)
	{
		//Get the size
		int size = prefix.Length;
		//Create stack object
		MyStack collection = new MyStack();
		//Some useful variables which is using of to storing current result
		String auxiliary = "";
		String op1 = "";
		String op2 = "";
		Boolean is_valid = true;
		for (int i = size - 1; i >= 0; i--)
		{
			//Check whether given prefix location at [i] is an operator or not
			if (prefix[i] == '+' || prefix[i] == '-' || prefix[i] == '*' || prefix[i] == '/' || prefix[i] == '^' || prefix[i] == '%')
			{
				// When operator exist
				// Check that two operands exist or not
				if (collection.is_two_operands() == true)
				{
					op1 = collection.pop();
					op2 = collection.pop();
					auxiliary = "(" + op1 + prefix[i] + op2 + ")";
					collection.push(auxiliary);
				}
				else
				{
					is_valid = false;
				}
			}
			else if ((prefix[i] >= '0' && prefix[i] <= '9') || (prefix[i] >= 'a' && prefix[i] <= 'z') || (prefix[i] >= 'A' && prefix[i] <= 'Z'))
			{
				auxiliary = "" + prefix[i];
				collection.push(auxiliary);
			}
			else
			{
				is_valid = false;
			}
		}
		if (is_valid == false)
		{
			Console.Write("Invalid Prefix : " + prefix);
		}
		else
		{
			Console.Write("\n Prefix : " + prefix);
			Console.Write("\n Infix  : " + collection.pop());
		}
	}
	public static void Main(String[] args)
	{
		MyStack obj = new MyStack();
		String prefix = "+*ab^cd";
		obj.infix_conversion(prefix);
		prefix = "-+*^%adcex*y^ab";
		obj.infix_conversion(prefix);
	}
}

Output

 Prefix : +*ab^cd
 Infix  : ((a*b)+(c^d))
 Prefix : -+*^%adcex*y^ab
 Infix  : (((((a%d)^c)*e)+x)-(y*(a^b)))

<?php
// Php program
// Prefix to infix 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;
	}
	//Check two operands exist or not
	public	function is_two_operands()
	{
		$counter = 0;
		$temp = $this->top;
		while ($temp != null && $counter < 2)
		{
			$counter++;
			$temp = $temp->next;
		}
		return $counter == 2;
	}
	//Add a new element in stack
	public	function push($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 $this->top->data;
		}
		else
		{
			return "";
		}
	}
	//Converting the given prefix expression to infix expression
	public	function infix_conversion($prefix)
	{
		//Get the size
		$size = strlen($prefix);
		//Create stack object
		$collection = new MyStack();
		//Some useful variables which is using of to storing current result
		$auxiliary = "";
		$op1 = "";
		$op2 = "";
		$is_valid = true;
		for ($i = $size - 1; $i >= 0; $i--)
		{
			//Check whether given prefix location at [i] is an operator or not
			if ($prefix[$i] == '+' || $prefix[$i] == '-' || $prefix[$i] == '*' || $prefix[$i] == '/' || $prefix[$i] == '^' || $prefix[$i] == '%')
			{
				// When operator exist
				// Check that two operands exist or not
				if ($collection->is_two_operands() == true)
				{
					$op1 = $collection->pop();
					$op2 = $collection->pop();
					$auxiliary = "(". $op1 . $prefix[$i] . $op2 .")";
					$collection->push($auxiliary);
				}
				else
				{
					$is_valid = false;
				}
			}
			else if ((ord($prefix[$i]) >= ord('0') && ord($prefix[$i]) <= ord('9')) || (ord($prefix[$i]) >= ord('a') && ord($prefix[$i]) <= ord('z')) || (ord($prefix[$i]) >= ord('A') && ord($prefix[$i]) <= ord('Z')))
			{
				$auxiliary =  $prefix[$i];
				$collection->push($auxiliary);
			}
			else
			{
				$is_valid = false;
			}
		}
		if ($is_valid == false)
		{
			echo "Invalid Prefix : ". $prefix;
		}
		else
		{
			echo "\n Prefix : ". $prefix;
			echo "\n Infix  : ". $collection->pop();
		}
	}
}

function main()
{
	$obj = new MyStack();
	$prefix = "+*ab^cd";
	$obj->infix_conversion($prefix);
	$prefix = "-+*^%adcex*y^ab";
	$obj->infix_conversion($prefix);
}
main();

Output

 Prefix : +*ab^cd
 Infix  : ((a*b)+(c^d))
 Prefix : -+*^%adcex*y^ab
 Infix  : (((((a%d)^c)*e)+x)-(y*(a^b)))

// Node Js program
// Prefix to infix conversion
//Stack Node
class Node
{
	constructor(data)
	{
		this.data = data;
		this.next = null;
	}
}
class MyStack
{
	constructor()
	{
		this.top = null;
	}
	//Check two operands exist or not
	is_two_operands()
	{
		var counter = 0;
		var temp = this.top;
		while (temp != null && counter < 2)
		{
			counter++;
			temp = temp.next;
		}
		return counter == 2;
	}
	//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 "";
		}
	}
	//Converting the given prefix expression to infix expression
	infix_conversion(prefix)
	{
		//Get the size
		var size = prefix.length;
		//Create stack object
		var collection = new MyStack();
		//Some useful variables which is using of to storing current result
		var auxiliary = "";
		var op1 = "";
		var op2 = "";
		var is_valid = true;
		for (var i = size - 1; i >= 0; i--)
		{
			//Check whether given prefix location at [i] is an operator or not
			if (prefix[i] == '+' || prefix[i] == '-' || prefix[i] == '*' || prefix[i] == '/' || prefix[i] == '^' || prefix[i] == '%')
			{
				// When operator exist
				// Check that two operands exist or not
				if (collection.is_two_operands() == true)
				{
					op1 = collection.pop();
					op2 = collection.pop();
					auxiliary = "(" + op1 + prefix[i] + op2 + ")";
					collection.push(auxiliary);
				}
				else
				{
					is_valid = false;
				}
			}
			else if (((prefix[i]).charCodeAt(0) >= ('0').charCodeAt(0) && (prefix[i]).charCodeAt(0) <= ('9').charCodeAt(0)) || ((prefix[i]).charCodeAt(0) >= ('a').charCodeAt(0) && (prefix[i]).charCodeAt(0) <= ('z').charCodeAt(0)) || ((prefix[i]).charCodeAt(0) >= ('A').charCodeAt(0) && (prefix[i]).charCodeAt(0) <= ('Z').charCodeAt(0)))
			{
				auxiliary = "" + prefix[i];
				collection.push(auxiliary);
			}
			else
			{
				is_valid = false;
			}
		}
		if (is_valid == false)
		{
			process.stdout.write("Invalid Prefix : " + prefix);
		}
		else
		{
			process.stdout.write("\n Prefix : " + prefix);
			process.stdout.write("\n Infix  : " + collection.pop());
		}
	}
}

function main()
{
	var obj = new MyStack();
	var prefix = "+*ab^cd";
	obj.infix_conversion(prefix);
	prefix = "-+*^%adcex*y^ab";
	obj.infix_conversion(prefix);
}
main();

Output

 Prefix : +*ab^cd
 Infix  : ((a*b)+(c^d))
 Prefix : -+*^%adcex*y^ab
 Infix  : (((((a%d)^c)*e)+x)-(y*(a^b)))

#  Python 3 program
#  Prefix to infix conversion

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

class MyStack :
	
	def __init__(self) :
		self.top = None
	
	# Check two operands exist or not
	def is_two_operands(self) :
		counter = 0
		temp = self.top
		while (temp != None and counter < 2) :
			counter += 1
			temp = temp.next
		
		return counter == 2
	
	# 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 ""
		
	
	# Converting the given prefix expression to infix expression
	def infix_conversion(self, prefix) :
		# Get the size
		size = len(prefix)
		# Create stack object
		collection = MyStack()
		# Some useful variables which is using of to storing current result
		auxiliary = ""
		op1 = ""
		op2 = ""
		is_valid = True
		i = size - 1
		while (i >= 0) :
			# Check whether given prefix location at [i] is an operator or not
			if (prefix[i] == '+'
				or prefix[i] == '-'
				or prefix[i] == '*'
				or prefix[i] == '/'
				or prefix[i] == '^'
				or prefix[i] == '%') :
				#  When operator exist
				#  Check that two operands exist or not
				if (collection.is_two_operands() == True) :
					op1 = collection.pop()
					op2 = collection.pop()
					auxiliary = "("+ op1 + prefix[i] + op2 +")"
					collection.push(auxiliary)
				else :
					is_valid = False
				
			
			elif((ord(prefix[i]) >= ord('0') and ord(prefix[i]) <= ord('9')) or(ord(prefix[i]) >= ord('a') and ord(prefix[i]) <= ord('z')) or(ord(prefix[i]) >= ord('A') and ord(prefix[i]) <= ord('Z'))) :
				auxiliary = prefix[i]
				collection.push(auxiliary)
			else :
				is_valid = False
			
			i -= 1
		
		if (is_valid == False) :
			print("Invalid Prefix : ", prefix, end = "")
		else :
			print("\n Prefix : ", prefix, end = "")
			print("\n Infix  : ", collection.pop(), end = "")
		
	

def main() :
	obj = MyStack()
	prefix = "+*ab^cd"
	obj.infix_conversion(prefix)
	prefix = "-+*^%adcex*y^ab"
	obj.infix_conversion(prefix)

if __name__ == "__main__": main()

Output

 Prefix :  +*ab^cd
 Infix  :  ((a*b)+(c^d))
 Prefix :  -+*^%adcex*y^ab
 Infix  :  (((((a%d)^c)*e)+x)-(y*(a^b)))

#  Ruby program
#  Prefix to infix 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
	# Check two operands exist or not
	def is_two_operands()
	
		counter = 0
		temp = self.top
		while (temp != nil && counter < 2)
		
			counter += 1
			temp = temp.next
		end
		return counter == 2
	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
	# Converting the given prefix expression to infix expression
	def infix_conversion(prefix)
	
		# Get the size
		size = prefix.length()
		# Create stack object
		collection = MyStack.new()
		# Some useful variables which is using of to storing current result
		auxiliary = ""
		op1 = ""
		op2 = ""
		is_valid = true
		i = size - 1
		while (i >= 0)
		
			# Check whether given prefix location at [i] is an operator or not
			if (prefix[i] == '+' || prefix[i] == '-' || prefix[i] == '*' || prefix[i] == '/' || prefix[i] == '^' || prefix[i] == '%')
			
				#  When operator exist
				#  Check that two operands exist or not
				if (collection.is_two_operands() == true)
				
					op1 = collection.pop()
					op2 = collection.pop()
					auxiliary = "("+ op1 + prefix[i] + op2 +")"
					collection.push(auxiliary)
				else
				
					is_valid = false
				end
			elsif(((prefix[i]).ord >= ('0').ord && (prefix[i]).ord <= ('9').ord) || ((prefix[i]).ord >= ('a').ord && (prefix[i]).ord <= ('z').ord) || ((prefix[i]).ord >= ('A').ord && (prefix[i]).ord <= ('Z').ord))
			
				auxiliary =  prefix[i]
				collection.push(auxiliary)
			else
			
				is_valid = false
			end
			i -= 1
		end
		if (is_valid == false)
		
			print("Invalid Prefix : ", prefix)
		else
		
			print("\n Prefix : ", prefix)
			print("\n Infix  : ", collection.pop())
		end
	end
end
def main()

	obj = MyStack.new()
	prefix = "+*ab^cd"
	obj.infix_conversion(prefix)
	prefix = "-+*^%adcex*y^ab"
	obj.infix_conversion(prefix)
end
main()

Output

 Prefix : +*ab^cd
 Infix  : ((a*b)+(c^d))
 Prefix : -+*^%adcex*y^ab
 Infix  : (((((a%d)^c)*e)+x)-(y*(a^b)))

// Scala program
// Prefix to infix 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);
	}
	//Check two operands exist or not
	def is_two_operands(): Boolean = {
		var counter: Int = 0;
		var temp: Node = this.top;
		while (temp != null && counter < 2)
		{
			counter += 1;
			temp = temp.next;
		}
		return counter == 2;
	}
	//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 "";
		}
	}
	//Converting the given prefix expression to infix expression
	def infix_conversion(prefix: String): Unit = {
		//Get the size
		var size: Int = prefix.length();
		//Create stack object
		var collection: MyStack = new MyStack();
		//Some useful variables which is using of to storing current result
		var auxiliary: String = "";
		var op1: String = "";
		var op2: String = "";
		var is_valid: Boolean = true;
		var i: Int = size - 1;
		while (i >= 0)
		{
			//Check whether given prefix location at [i] is an operator or not
			if (prefix(i) == '+' || prefix(i) == '-' || prefix(i) == '*' || prefix(i) == '/' || prefix(i) == '^' || prefix(i) == '%')
			{
				// When operator exist
				// Check that two operands exist or not
				if (collection.is_two_operands() == true)
				{
					op1 = collection.pop();
					op2 = collection.pop();
					auxiliary = "(" + op1 + prefix(i) + op2 + ")";
					collection.push(auxiliary);
				}
				else
				{
					is_valid = false;
				}
			}
			else if ((prefix(i) >= '0' && prefix(i) <= '9') || (prefix(i) >= 'a' && prefix(i) <= 'z') || (prefix(i) >= 'A' && prefix(i) <= 'Z'))
			{
				auxiliary = "" + prefix(i);
				collection.push(auxiliary);
			}
			else
			{
				is_valid = false;
			}
			i -= 1;
		}
		if (is_valid == false)
		{
			print("Invalid Prefix : " + prefix);
		}
		else
		{
			print("\n Prefix : " + prefix);
			print("\n Infix  : " + collection.pop());
		}
	}
}
object Main
{
	def main(args: Array[String]): Unit = {
		var obj: MyStack = new MyStack();
		var prefix: String = "+*ab^cd";
		obj.infix_conversion(prefix);
		prefix = "-+*^%adcex*y^ab";
		obj.infix_conversion(prefix);
	}
}

Output

 Prefix : +*ab^cd
 Infix  : ((a*b)+(c^d))
 Prefix : -+*^%adcex*y^ab
 Infix  : (((((a%d)^c)*e)+x)-(y*(a^b)))

// Swift program
// Prefix to infix 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;
	}
	//Check two operands exist or not
	func is_two_operands() -> Bool
	{
		var counter: Int = 0;
		var temp: Node? = self.top;
		while (temp != nil && counter < 2)
		{
			counter += 1;
			temp = temp!.next;
		}
		return counter == 2;
	}
	//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 "";
		}
	}
	//Converting the given prefix expression to infix expression
	func infix_conversion(_ exp: String)
	{
      	let prefix = Array(exp);
		//Get the size
		let size: Int = prefix.count;
		//Create stack object
		let collection: MyStack = MyStack();
		//Some useful variables which is using of to storing current result
		var auxiliary: String = "";
		var op1: String = "";
		var op2: String = "";
		var is_valid: Bool = true;
		var i: Int = size - 1;
		while (i >= 0)
		{
			//Check whether given prefix location at [i] is an operator or not
			if (prefix[i] == "+" || prefix[i] == "-" || prefix[i] == "*" || prefix[i] == "/" || prefix[i] == "^" || prefix[i] == "%")
			{
				// When operator exist
				// Check that two operands exist or not
				if (collection.is_two_operands() == true)
				{
					op1 = collection.pop();
					op2 = collection.pop();
					auxiliary = "(" + op1 + String(prefix[i]) + op2 + ")";
					collection.push(auxiliary);
				}
				else
				{
					is_valid = false;
				}
			}
			else if ((prefix[i] >= "0" && prefix[i] <= "9") || (prefix[i] >= "a" && prefix[i] <= "z") || (prefix[i] >= "A" && prefix[i] <= "Z"))
			{
				auxiliary =  String(prefix[i]);
				collection.push(auxiliary);
			}
			else
			{
				is_valid = false;
			}
			i -= 1;
		}
		if (is_valid == false)
		{
			print("Invalid Prefix : ", exp, terminator: "");
		}
		else
		{
			print("\n Prefix : ", exp, terminator: "");
			print("\n Infix  : ", collection.pop(), terminator: "");
		}
	}
}
func main()
{
	let obj: MyStack = MyStack();
	var prefix: String = "+*ab^cd";
	obj.infix_conversion(prefix);
	prefix = "-+*^%adcex*y^ab";
	obj.infix_conversion(prefix);
}
main();

Output

 Prefix :  +*ab^cd
 Infix  :  ((a*b)+(c^d))
 Prefix :  -+*^%adcex*y^ab
 Infix  :  (((((a%d)^c)*e)+x)-(y*(a^b)))

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