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javascriptspidermonkey

Javascript Skipping Adjacent Value as Undefined

I'm trying to write a program that looks for perfect and almost perfect numbers. 

var num = readline();

function sumDivisors(num){
  var sum = 0;
  for (var i = 1; i < num; i++){
    if (!(num % i)) {
      sum += i;
    }
  }
  if ( sum == num ) {
     print(num + " perfect");
   }
  if ( (sum - num == 2) || (sum - num == -2) ) {
     print(num + " almost perfect");
   }
  if ( ( sum != num ) && (sum - num != 2) && (sum - num != -2) ) {
     print(num + " not perfect");
   }
  while(readline()){
     sumDivisors(readline());
   }
}

print(sumDivisors(num));

It accepts a number of inputs from the user, and outputs perfect for perfect numbers, almost perfect for almost perfect numbers, and not perfect for... well, you get it.

Sample Input/Output

enter image description here

My Question:

I'm almost there. The code above seems to work, except for one thing. The while loop skips adjacent values and marks them as undefined.

For example, when I input 6,43,2,650,28, the output will be 6 - perfect, [43 will be skipped], 2 - not perfect, [650 will be skipped], 28 - perfect, undefined.

Problematic Output

enter image description here

Solution

  • You are calling readline() twice in each loop:

    while(readline()){          // <-- here
   sumDivisors(readline()); // <-- again here
}

    Since you aren't doing anything with the first one, it's just removing the number from the list. An easy fix is to save the result in the while() test:

    while((n = readline())){
   sumDivisors(n);
}

    or better yet:

    if((n = readline())){ // <-- you don't need a loop here since you have recursion
   sumDivisors(n);
}

    You are also calling print on sumDivisors() which doesn't return anything: print(sumDivisors(num)); This is why you are getting the undefined line in your output.