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infix to postfix kotlin

Muhammad Umair Ali answered on December 16, 2022 Popularity 1/10 Helpfulness 3/10

answer infix to postfix kotlin

infix to postfix kotlin

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// Kotlin program for
// Infix to postfix conversion
// Using custom stack

// Stack node
class StackNode
{
	// Stack data
	var element: Char;
	var next: StackNode ? ;
	constructor(element: Char, next: StackNode ? )
	{
		this.element = element;
		this.next = next;
	}
}
// Define a custom stack
class MyStack
{
	var top: StackNode ? ;
	var size: Int;
	constructor()
	{
		this.top = null;
		this.size = 0;
	}
	// Add node at the top of stack
	fun push(element: Char): Unit
	{
		this.top = StackNode(element, this.top);
		this.size += 1;
	}
	fun isEmpty(): Boolean
	{
		if (this.size > 0 && this.top != null)
		{
			return false;
		}
		else
		{
			return true;
		}
	}
	// Remove top element of stack
	fun pop(): Unit
	{
		if (this.size > 0 && this.top != null)
		{
			// Change top element of stack
			this.top = this.top!!.next;
			this.size -= 1;
		}
	}
	// Return top element of stack
	fun peek(): Char
	{
		if (this.top == null)
		{
			return ' ';
		}
		return this.top!!.element;
	}
}
class Conversion
{
	fun precedence(text: Char): Int
	{
		if (text == '+' || text == '-')
		{
			return 1;
		}
		else if (text == '*' || text == '/')
		{
			return 2;
		}
		else if (text == '^')
		{
			return 3;
		}
		return -1;
	}
	fun is_operator(text: Char): Boolean
	{
		if (text == '+' || text == '-' || 
            text == '*' || text == '/' || text == '^')
		{
			return true;
		}
		return false;
	}
	// Converting the given infix expression to postfix expression
	fun infixToPostfix(infix: String): Unit
	{
		var result: String = "";
		// Get the size
		val size: Int = infix.length;
		// Create empty stack 
		val s: MyStack = MyStack();
		var i: Int = 0;
		while (i < size)
		{
			if ((infix.get(i) >= '0' && 
                 infix.get(i) <= '9') || 
                (infix.get(i) >= 'a' && infix.get(i) <= 'z') || 
                (infix.get(i) >= 'A' && infix.get(i) <= 'Z'))
			{
				// When getting a operands
				result = result + infix.get(i).toString();
			}
			else
			{
				if (s.isEmpty() || infix.get(i) == '(')
				{
					// Base case
					// When getting a open parenthesis
					// Or stack is empty
					s.push(infix.get(i));
				}
				else if (infix.get(i) == ')')
				{
					// Need to remove stack element until the close bracket
					while (s.isEmpty() == false && s.peek() != '(')
					{
						// Get top element
						result += s.peek();
						// Remove stack element
						s.pop();
					}
					if (s.peek() == '(')
					{
						// Remove stack element
						s.pop();
					}
				}
				else
				{
					// Remove stack element until precedence of 
					// top is greater than current infix operator
					while (s.isEmpty() == false && this.precedence(infix.get(i)) <= this.precedence(s.peek()))
					{
						// Get top element
						result += s.peek();
						// Remove stack element
						s.pop();
					}
					// Add new operator
					s.push(infix.get(i));
				}
			}
			i += 1;
		}
		// Add remaining elements
		while (s.isEmpty() == false)
		{
			result += s.peek();
			s.pop();
		}
		// Display result
		println(" Infix    : " + infix);
		println(" Postfix  : " + result);
	}
}
fun main(args: Array < String > ): Unit
{
	val task: Conversion = Conversion();
	var infix: String = "((a/b+c))/(e*f)+(g^h-i)+k";
	task.infixToPostfix(infix);
	infix = "((a*b)^(c+d)/e)-f";
	task.infixToPostfix(infix);
}

Popularity 1/10 Helpfulness 3/10 Language whatever

Source: kalkicode.com

Tags: kotlin postfix whatever

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Contributed on Dec 16 2022

Muhammad Umair Ali

0 Answers Avg Quality 2/10

infix to postfix kotlin

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