trimill.xyz/flaskr/templates/projects/fracbase/index.html

96 lines
3.3 KiB
HTML

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