Amit Prajapati

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# Write the program to convert the binary to decimal ?

Binary is the number system all digital computers are based on. Therefore it's important for developers to understand binary, or base 2, mathematics. The purpose of Bin2Dec is to provide practice and understanding of how binary calculations
app.js

``````let decimal = document.getElementById('decimal');
let binary = document.getElementById('binary');
let error = document.getElementById('error');
let binaryNumber = '';
let maxInputLength = 10;
error.innerHTML = '';
if (binaryNumber.length == maxInputLength) {
error.innerHTML = `You can enter only \${maxInputLength} the length of the binary`;
return e.preventDefault();
}
if (!(e.key == 0 || e.key == 1)) {
error.innerHTML = 'Invalid key press';
binaryNumber.replace(e.key, '', '');
binary.value = binaryNumber;
e.preventDefault();
return false;
}
binaryNumber += e.key
decimal.innerHTML = binaryNumber;
})
let count = 0;
let decimalNumber = 0;
if (!binaryNumber.length) {
return e.preventDefault();
}
for (let j = binaryNumber.length; j > 0; j--) {
decimalNumber += Number(getDecimalNumber(j,Number(binaryNumber[count])))
count++;
}
decimal.innerHTML = decimalNumber;
decimalNumber = 0
})

function getDecimalNumber(count,binary) {
let n = 0;
switch (count) {
case 1: n = binary ? 1 : 0; break;
case 2: n = binary ? 2 : 0; break;
case 3: n = binary ? 4 : 0; break;
case 4: n = binary ? 8 : 0; break;
case 5: n = binary ? 16 : 0; break;
case 6: n = binary ? 32 : 0; break;
case 7: n = binary ? 64 : 0; break;
case 8: n = binary ? 128 : 0; break;
case 9: n = binary ? 256 : 0; break;
case 10: n = binary ? 512 : 0; break;
}
return n;
}
``````

index.html

``````<!DOCTYPE html>
<html>
<body>
<h2 style="text-align: center">Binary to Decimal conversion</h2>
<div style="text-align: center">
<form>
<div id="decimal">0</div><br>