We are required to write a JavaScript function that takes in two numbers, say, a and b and returns the total number of prime numbers between a and b (including a and b, if they are prime).
For example: If a = 21, and b = 38.
The prime numbers between them are 23, 29, 31, 37
And their count is 4
Our function should return 4
Example
The code for this will be −
const isPrime = num => { let count = 2; while(count < (num / 2)+1){ if(num % count !== 0){ count++; continue; }; return false; }; return true; }; const primeBetween = (a, b) => { let count = 0; for(let i = Math.min(a, b); i <= Math.max(a, b); i++){ if(isPrime(i)){ count++; }; }; return count; }; console.log(primeBetween(21, 38));
Output
The output in the console −
4