Michaelgathara/polish-notation.html

## polish-notation.html
<!DOCTYPE html>
<!-- THIS IS CODE DONE IN 20 MINUTES, NOT THE BEST LOOKING CODE OUT THERE -->
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Infix to Prefix Notation Converter</title>
    <style>
      @import url("https://fonts.googleapis.com/css2?family=Roboto&display=swap");
      body,
      html {
        margin: 0 auto;
        font-family: "Roboto", sans-serif;
        font-weight: 400;
        font-style: normal;
        text-align: center;
      }
    </style>
  </head>
  <body>
    <h1>Infix to Prefix</h1>
    <p>
      Parans will dissapear, but it does take them into account, ie: (1 + 2) * 3
      vs 1 + 2 * 3
    </p>

    <label for="infixInput">Enter Infix Expression:</label>
    <br /><br />
    <input type="text" id="infixInput" placeholder="e.g., (1 + 2) * 3" />
    <br /><br />
    <button onclick="convertToPrefix()">Convert</button>

    <p>Prefix Notation:</p>
    <br /><br />
    <p id="prefixOutput"></p>

    <br /><br /><br /><br />
    <p>
      The code for this is here:
      <a
        href="https://gist.github.com/Michaelgathara/cac0cce5859c681afc9a703e63d0761f"
        >https://gist.github.com/Michaelgathara/cac0cce5859c681afc9a703e63d0761f</a
      >
    </p>

    <script>
      function getPrecedence(op) {
        if (op === "+" || op === "-") {
          return 1;
        }
        if (op === "*" || op === "/") {
          return 2;
        }
        return 0;
      }

      function infixToPrefix(infix) {
        let opsStack = [];
        let operandsStack = [];

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

          if (!isNaN(parseInt(token))) {
            operandsStack.push(token);
          }
          else if (token === "(") {
            opsStack.push(token);
          }
          else if (token === ")") {
            while (
              opsStack.length > 0 &&
              opsStack[opsStack.length - 1] !== "("
            ) {
              const operator = opsStack.pop();
              const rightOperand = operandsStack.pop();
              const leftOperand = operandsStack.pop();
              const newExpr = operator + leftOperand + rightOperand;
              operandsStack.push(newExpr);
            }
            opsStack.pop();
          }
          else if (getPrecedence(token) > 0) {
            while (
              opsStack.length > 0 &&
              getPrecedence(token) <=
                getPrecedence(opsStack[opsStack.length - 1])
            ) {
              const operator = opsStack.pop();
              const rightOperand = operandsStack.pop();
              const leftOperand = operandsStack.pop();
              const newExpr = operator + leftOperand + rightOperand;
              operandsStack.push(newExpr);
            }
            opsStack.push(token);
          }
        }

        while (opsStack.length > 0) {
          const operator = opsStack.pop();
          const rightOperand = operandsStack.pop();
          const leftOperand = operandsStack.pop();
          const newExpr = operator + leftOperand + rightOperand;
          operandsStack.push(newExpr);
        }

        return operandsStack[operandsStack.length - 1];
      }

      function convertToPrefix() {
        let infix = document
          .getElementById("infixInput")
          .value.replace(/\s+/g, "");
        let prefix = infixToPrefix(infix);
        document.getElementById("prefixOutput").textContent = prefix;
      }
    </script>
  </body>
</html>
	<!DOCTYPE html>
	<!-- THIS IS CODE DONE IN 20 MINUTES, NOT THE BEST LOOKING CODE OUT THERE -->
	<html lang="en">
	<head>
	<meta charset="UTF-8" />
	<meta name="viewport" content="width=device-width, initial-scale=1.0" />
	<title>Infix to Prefix Notation Converter</title>
	<style>
	@import url("https://fonts.googleapis.com/css2?family=Roboto&display=swap");
	body,
	html {
	margin: 0 auto;
	font-family: "Roboto", sans-serif;
	font-weight: 400;
	font-style: normal;
	text-align: center;
	}
	</style>
	</head>
	<body>
	<h1>Infix to Prefix</h1>
	<p>
	Parans will dissapear, but it does take them into account, ie: (1 + 2) * 3
	vs 1 + 2 * 3
	</p>

	<label for="infixInput">Enter Infix Expression:</label>
	<br /><br />
	<input type="text" id="infixInput" placeholder="e.g., (1 + 2) * 3" />
	<br /><br />
	<button onclick="convertToPrefix()">Convert</button>

	<p>Prefix Notation:</p>
	<br /><br />
	<p id="prefixOutput"></p>

	<br /><br /><br /><br />
	<p>
	The code for this is here:
	<a
	href="https://gist.github.com/Michaelgathara/cac0cce5859c681afc9a703e63d0761f"
	>https://gist.github.com/Michaelgathara/cac0cce5859c681afc9a703e63d0761f</a
	>
	</p>

	<script>
	function getPrecedence(op) {
	if (op === "+" \|\| op === "-") {
	return 1;
	}
	if (op === "*" \|\| op === "/") {
	return 2;
	}
	return 0;
	}

	function infixToPrefix(infix) {
	let opsStack = [];
	let operandsStack = [];

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

	if (!isNaN(parseInt(token))) {
	operandsStack.push(token);
	}
	else if (token === "(") {
	opsStack.push(token);
	}
	else if (token === ")") {
	while (
	opsStack.length > 0 &&
	opsStack[opsStack.length - 1] !== "("
	) {
	const operator = opsStack.pop();
	const rightOperand = operandsStack.pop();
	const leftOperand = operandsStack.pop();
	const newExpr = operator + leftOperand + rightOperand;
	operandsStack.push(newExpr);
	}
	opsStack.pop();
	}
	else if (getPrecedence(token) > 0) {
	while (
	opsStack.length > 0 &&
	getPrecedence(token) <=
	getPrecedence(opsStack[opsStack.length - 1])
	) {
	const operator = opsStack.pop();
	const rightOperand = operandsStack.pop();
	const leftOperand = operandsStack.pop();
	const newExpr = operator + leftOperand + rightOperand;
	operandsStack.push(newExpr);
	}
	opsStack.push(token);
	}
	}

	while (opsStack.length > 0) {
	const operator = opsStack.pop();
	const rightOperand = operandsStack.pop();
	const leftOperand = operandsStack.pop();
	const newExpr = operator + leftOperand + rightOperand;
	operandsStack.push(newExpr);
	}

	return operandsStack[operandsStack.length - 1];
	}

	function convertToPrefix() {
	let infix = document
	.getElementById("infixInput")
	.value.replace(/\s+/g, "");
	let prefix = infixToPrefix(infix);
	document.getElementById("prefixOutput").textContent = prefix;
	}
	</script>
	</body>
	</html>