postfix0001

<script>

// JavaScript program to convert
// infix to prefix.

// Function to check if
// given character is
// an operator or not.
function isOperator(c)
{
	return (!(c >= 'a' && c <= 'z') &&
			!(c >= '0' && c <= '9') &&
			!(c >= 'A' && c <= 'Z'));
}

// Function to find priority
// of given operator.
function getPriority(C)
{
	if (C == '-' || C == '+')
		return 1;
	else if (C == '*' || C == '/')
		return 2;
	else if (C == '^')
		return 3;
	return 0;
}

// Function that converts infix
// expression to prefix expression.
function infixToPrefix(infix)
{
	// stack for operators.
	let operators = [];

	// stack for operands.
	let operands = [];

	for (let i = 0; i < infix.length; i++)
	{

		// If current character is an
		// opening bracket, then
		// push into the operators stack.
		if (infix[i] == '(')
		{
			operators.push(infix[i]);
		}

		// If current character is a
		// closing bracket, then pop from
		// both stacks and push result
		// in operands stack until
		// matching opening bracket is
		// not found.
		else if (infix[i] == ')')
		{
			while (operators.length!=0 &&
				operators[operators.length-1] != '(')
				{

				// operand 1
				let op1 = operands.pop();
				

				// operand 2
				let op2 = operands.pop();
				

				// operator
				let op = operators.pop();
				

				// Add operands and operator
				// in form operator +
				// operand1 + operand2.
				let tmp = op + op2 + op1;
				operands.push(tmp);
			}

			// Pop opening bracket
			// from stack.
			operators.pop();
		}

		// If current character is an
		// operand then push it into
		// operands stack.
		else if (!isOperator(infix[i]))
		{
			operands.push(infix[i] + "");
		}

		// If current character is an
		// operator, then push it into
		// operators stack after popping
		// high priority operators from
		// operators stack and pushing
		// result in operands stack.
		else
		{
			while (operators.length &&
				getPriority(infix[i]) <=
					getPriority(operators[operators.length-1]))
				{

				let op1 = operands.pop();
				

				let op2 = operands.pop();
				

				let op = operators.pop();
				

				let tmp = op + op2 + op1;
				operands.push(tmp);
			}

			operators.push(infix[i]);
		}
	}

	// Pop operators from operators
	// stack until it is empty and
	// operation in add result of
	// each pop operands stack.
	while (operators.length!=0)
	{
		let op1 = operands.pop();
		

		let op2 = operands.pop();
		

		let op = operators.pop();
		

		let tmp = op + op2 + op1;
		operands.push(tmp);
	}

	// Final prefix expression is
	// present in operands stack.
	return operands[operands.length-1];
}

// Driver code
let s = "(A-B/C)*(A/K-L)";
document.write( infixToPrefix(s));


// This code is contributed by avanitrachhadiya2155

</script>