编写一个函数，以正整数为参数，并显示小于或等于它的所有素数之和。

解决方案

// define a function named addprimesum that takes a single parameter 'number'
function addprimesum(number) {
  // initialize a variable 'result' to store the sum of prime numbers, starting from 0
  let result = 0;

  // define an inner function named isprime that takes a single parameter 'num'
  function isprime(num) {
    // if 'num' is less than 2, it is not prime, so return nothing (undefined)
    if (num < 2) return;

    // loop from 2 to half of 'num' to check for factors
    for (let i = 2; i <= num / 2; i++) {
      // if 'num' is divisible by 'i', it's not prime, so return nothing (undefined)
      if (num % i === 0) return;
    }
    // if no factors are found, return 'num' indicating it is a prime number
    return num;
  }

  // loop while 'number' is greater than 1
  while (number > 1) {
    // check if 'number' is prime using the isprime function
    if (isprime(number)) {
      // if it is prime, add it to 'result'
      result += number;
    }
    // decrement 'number' by 1 to check the next lower number
    number--;
  }

  // return the total sum of all prime numbers found
  return result;
}

console.log(addprimesum(5));
console.log(addprimesum(21));
console.log(addprimesum(100));
console.log(addprimesum(239));
console.log(addprimesum(956));

解决方案

> 10
> 77
> 1060
> 5589
> 70241