Hackerrank Day 2: Operators

Given the mealCost, tipPercent (the percentage of the meal price being added as tip), and taxPercent (the percentage of the meal price being added as tax) for a meal, find and print the meal’s totalCost.


My solution in Ruby: 

# gets user input and convert them to float

mealCost = gets.to_f
tipPercent = gets.to_f
taxPercent = gets.to_f

tip = mealCost * (tipPercent / 100.0)
tax = mealCost * (taxPercent / 100.0)

totalCost = (mealCost + tip + tax).round

puts “The total meal cost is #{totalCost} dollars.”

I made one seemingly minor but critical mistake when I first solved the problem.  I divided tipPercent and tax Percent by 100, instead of 100.0.  This does not yield the same result in codes because when the computer divides by an integer (whole number) and not a float (decimals), it rounds the result to the nearest integer (which in this case, 20/100 = 0).  To get a float as your results, you have to change the values in the math operation to floats as well.

Hackerrank Day 2: Operators

Hackerrank Day 1: Data Types

Complete the code in the editor below. The variables i, d, s and are already declared and initialized for you. You must:

  1. Declare 3 variables: one of type int, one of type double, and one of type String.
  2. Read 3  lines of input from stdin (according to the sequence given in the Input Format section below) and initialize your variables.
  3. Use the operator to perform the following operations:
    1. Print the sum of i plus your int variable on a new line.
    2. Print the sum of d plus your double variable to a scale of one decimal place on a new line.
    3. Concatenate s with the string you read as input and print the result on a new line.

Sample Input

is the best place to learn and practice coding!

Sample Output

HackerRank is the best place to learn and practice coding!


When we sum the integers 4  and 12 , we get the integer 16.
When we sum the floating-point numbers 4.0 and 4.0, we get 8.0.
When we concatenate HackerRank with is the best place to learn and practice coding!, we get HackerRank is the best place to learn and practice coding!.

My solution in Ruby:

# Declare second integer, double, and String variables.

# Read and save an integer, double, and String to your variables.
i2 = gets.to_i
d2 = gets.to_f
s2 = gets.to_s

# Print the sum of both integer variables on a new line.
puts (i + i2)

# Print the sum of the double variables on a new line.
puts (d + d2)

# Concatenate and print the String variables on a new line
# The ‘s’ variable above should be printed first.
puts (s + s2)

Hackerrank Day 1: Data Types

Sum Nums

(First problem that I was able to solve without looking at the solution!)

Write a method that takes in an integer ‘num’ and returns the sum of all integers between zero and num, up to and including ‘num’.

Screen Shot 2016-08-11 at 12.10.35 PM

Basically, you want to write a simplified version of i + (i+1) + (i+2)…(i+num).

This doesn’t seem to take into account negative integers though?

Second time doing this problem, I got this:


Not as simple as my first one but it also works.

Sum Nums