96 lines
3.3 KiB
HTML
96 lines
3.3 KiB
HTML
{% set meta={"title": "Fraction to base n", "desc": "Convert fractions to digit expansions in different bases"} %}
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{% extends "/_base.html" %}
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{% block head %}
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<script>
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const SYMBOLS = "0123456789abcdefghijklmnopqrstuvwxyz";
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function getInputs() {
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const errorDiv = document.getElementById("error");
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error.textContent = "";
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const numer = parseInt(document.getElementById("numer").value);
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const denom = parseInt(document.getElementById("denom").value);
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const base = parseInt(document.getElementById("base").value);
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const digits = parseInt(document.getElementById("digits").value);
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if(isNaN(numer) || isNaN(denom) || isNaN (base) || isNaN(digits)) {
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errorDiv.textContent = "Error: inputs must be integers";
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return;
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}
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const blockform = document.getElementById("blockform").checked;
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if(denom === 0) {
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errorDiv.textContent = "Error: denominator must be nonzero";
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return;
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}
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if(base < 2) {
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errorDiv.textContent = "Error: base must be 2 or greater";
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return;
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}
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if(!blockform && base > 36) {
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errorDiv.textContent = "Error: bases greater than 36 require block form";
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return;
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}
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if(digits < 0) {
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errorDiv.textContent = "Error: digit count must be nonnegative";
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return;
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}
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return [numer, denom, base, digits, blockform];
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}
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function calc() {
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[numer, denom, base, digits, blockform] = getInputs();
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console.log(numer, denom, base, digits, blockform);
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const sign = Math.sign(numer * denom);
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numer = Math.abs(numer);
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denom = Math.abs(denom);
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const intpart = Math.floor(numer / denom);
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const fracpart = numer % denom;
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// int part
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let intpartDigits = [];
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let num = intpart;
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while(num !== 0) {
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intpartDigits.push(num % base);
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num = Math.floor(num / base);
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}
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intpartDigits.reverse();
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let fracpartDigits = [];
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num = fracpart;
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for(let i = 0; i < digits && num !== 0; i++) {
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num *= base;
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fracpartDigits.push(Math.floor(num / denom));
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num %= denom
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}
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let result = (sign === -1 ? "-" : "");
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if(blockform) {
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let intpartStr = intpartDigits.join(":");
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if(intpartStr.length == 0) { intpartStr = "0"; }
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let fracpartStr = fracpartDigits.join(":")
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if(fracpartStr.length > 0) { fracpartStr = "." + fracpartStr + ":"; }
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result += intpartStr + fracpartStr;
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} else {
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let intpartStr = intpartDigits.map(x => SYMBOLS[x]).join("");
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if(intpartStr.length == 0) { intpartStr = "0"; }
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let fracpartStr = fracpartDigits.map(x => SYMBOLS[x]).join("")
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if(fracpartStr.length > 0) { fracpartStr = "." + fracpartStr; }
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result += intpartStr + fracpartStr;
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}
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document.getElementById("result").textContent = result;
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}
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</script>
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{% endblock%}
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{% block content%}
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<div>Numerator: <input type="number" id="numer" /></div>
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<div>Denominator: <input type="number" id="denom" /></div>
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<div>Base: <input type="number" id="base" /></div>
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<div>Digits: <input type="number" id="digits" /></div>
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<div><input type="checkbox" id="blockform" /> Show block form</div>
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<div><input type="button" id="calc" value="Calculate" onclick="calc();" /></div>
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<div>Result: <span id="result" style="color: var(--accent-2);"></span></div>
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<div id="error" class="error"></div>
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{% endblock %}
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