Solutions for Simple Adding
View the challenge

Official solution

This challenge requires you to add up all the numbers from 1 to a given argument. For example, if the parameter num is 4, your program should add up 1 + 2 + 3 + 4 and return 10. This will be pretty simple to write out as a loop. We'll maintain a variable and keep adding to it as we loop from 1 to num.

function SimpleAdding(num) { 

  var answer = 0;

  // loop from 1 to num
  for (var i = 1; i <= num; i++) {
    answer = answer + i;
  } 

  return answer;
         
}

SimpleAdding(4);                                                    
def SimpleAdding(num): 
  
  answer = 0

  # loop from 1 to num
  for i in range(1, num+1):
    answer = answer + i
    
  return answer
    
print SimpleAdding(4)  
def SimpleAdding(num)

  answer = 0
  
  # loop from 1 to num
  (1..num).each do |i|
    answer += i
  end
  
  return answer
         
end
     
puts SimpleAdding(STDIN.gets)    

There is also a very clever way to calculate the sum of the numbers 1 + 2 + 3 + .... The sum of the first N natural numbers is equal to n(n+1)/2 (see proof and why this is so).

function SimpleAdding(num) { 

  return (num*(num+1))/2;
         
}

SimpleAdding(4);                                                    
def SimpleAdding(num): 
  
  return (num*(num+1))/2
    
print SimpleAdding(4)  
def SimpleAdding(num) 
  
  return (num*(num+1))/2
    
end

puts SimpleAdding(STDIN.gets)  

Top Rated User Solution

loading...
loading...
loading...
loading...
loading...
loading...
loading...
Top User Solutions

Loading...