For some number y and some divisor x compute the quotient (quotient)[1] and remainder (remainder) as:
const quotient = Math.floor(y/x);
const remainder = y % x;
Example:
const quotient = Math.floor(13/3); // => 4 => the times 3 fits into 13
const remainder = 13 % 3; // => 1
[1] The integer number resulting from the division of one number by another
Answer from Mark Elliot on Stack Overflowmath - How to perform an integer division, and separately get the remainder, in JavaScript - Stack Overflow
Understanding the JavaScript Modulo Operator
Javascript - Setting the remainder operator
I think that's a typo, despite technically being "correct" (2 % 11 = 2).
Finding a Remainder in JavaScript help me pease
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For some number y and some divisor x compute the quotient (quotient)[1] and remainder (remainder) as:
const quotient = Math.floor(y/x);
const remainder = y % x;
Example:
const quotient = Math.floor(13/3); // => 4 => the times 3 fits into 13
const remainder = 13 % 3; // => 1
[1] The integer number resulting from the division of one number by another
I'm no expert in bitwise operators, but here's another way to get the whole number:
var num = ~~(a / b);
This will work properly for negative numbers as well, while Math.floor() will round in the wrong direction.
This seems correct as well:
var num = (a / b) >> 0;
Note: Only use ~~ as a substitution for Math.trunc() when you are confident that the range of input falls within the range of 32-bit integers.
Hi, Can anyone help me with the following. It's a question from https://www.freecodecamp.org/challenges/finding-a-remainder-in-javascript
Finding a Remainder in JavaScript
The remainder operator % gives the remainder of the division of two numbers.
Example
5 % 2 = 1 because Math.floor(5 / 2) = 2 (Quotient) 2 * 2 = 4 5 - 4 = 1 (Remainder)
Usage
In mathematics, a number can be checked even or odd by checking the remainder of the division of the number by 2.
17 % 2 = 1 (17 is Odd) 48 % 2 = 0 (48 is Even)
Note
The remainder operator is sometimes incorrectly referred to as the "modulus" operator. It is very similar to modulus, but does not work properly with negative numbers.
Instructions
Set remainder equal to the remainder of 11 divided by 3 using the remainder (%) operator.
-
The variable remainder should be initialized
Answer: var remainder; -
The value of remainder should be 2
Answer: var remainder = 2; -
You should use the % operator
Answer: var remainder = 2 % 11;
My question
I understand everything up until the final question in the instructions. That is, I don't understand how the answer 2 % 11 sets remainder equal to the remainder of 11 divided by 3 using the remainder (%) operator. Can anyone help me with this? Thanks.
If you think about the mathematical process to calculate modulus you might be able see how you can do this without having to resort to a bunch of case statements. Instead think of it this way, you're just calculating a remainder:
Given 2 numbers a and b, you can compute mod(a,b) by doing the following:
q = a / b; //finding quotient (integer part only)
p = q * b; //finding product
remainder = a - p; //finding modulus
Using this idea, you should be able to transfer it to JS. You said you're not looking for the straight up answer so that's all I'll say!
Edit: here is the code, like I said in the comments it's exactly the pseudocode I posted above:
function modulo(a,b){
q = parseInt(a / b); //finding quotient (integer part only)
p = q * b; //finding product
return a - p; //finding modulus
}
This will return the exact same values as using %
You might be overthinking this. You basically stated the solution in your question:
I need to carry over whichever sign is on num1, and also return a positive number if the num2 is negative
The second part isn't accurate, but I suspect you just misspoke. A positive number should be returned when num2 is negative unless num1 is negative.
At any rate, the important takeaway is that if num1 is negative the result will be negative, and otherwise the result will be positive. The sign of num2 is discarded.
Starting the code you've written (which others will be quick to point out isn't the simplest solution), the fix is to compute the remainder using both numbers' absolute values, and then apply num1's original sign to the result.
function modulo(num1, num2) {
var sign = num1 < 0 ? -1 : 1;
var dividend = Math.abs(num1);
var divisor = Math.abs(num2);
if (dividend === 0) {
return 0;
}
if (dividend === 0 || isNaN(dividend) || isNaN(divisor)) {
return NaN;
}
if (dividend < divisor) {
return sign * dividend;
}
var counter = dividend;
while (counter >= divisor) {
counter = counter - divisor;
}
return sign * counter;
}
console.log( 25 % 4, modulo( 25, 4));
console.log(-25 % 4, modulo(-25, 4));
console.log( 25 % -4, modulo( 25, -4));
console.log(-25 % -4, modulo(-25, -4));.as-console-wrapper{min-height:100%;}