js_excersizes.js

// # Write a method that prints out the numbers 1 to 1000 that are divisible by 3.
// def print_numbers_divisible_by_three
//   index = 1
//   while index <= 1000
//     if index % 3 == 0
//       puts index
//     end
//     index += 1
//   end
// end
// print_numbers_divisible_by_three
function printNumbersDivisibleByThree() {
  var index = 1;
  while (index <= 1000) {
    if (index % 3 === 0) {
      console.log(index);
    }
    index += 1;
  }
}
printNumbersDivisibleByThree();




// # Write a method that accepts an array of strings and prints out every other string.
// def print_every_other_item(strings)
//   index = 0
//   strings.each do |string|
//     if index % 2 == 0
//       puts string
//     end
//     index += 1
//   end
// end
// print_every_other_item(["a", "b", "c", "d", "e"])
function printEveryOtherItem(strings) {
  var index = 0;
  strings.forEach(function(string) {
    if (index % 2 === 0) {
      console.log(string);
    }
    index += 1;
  });
}
printEveryOtherItem(["a", "b", "c", "d", "e"]);


// # Write a method that accepts an array of numbers and returns the sum.
// def compute_sum(numbers)
//   sum = 0
//   numbers.each do |number|
//     sum += number
//   end
//   return sum
// end
// puts compute_sum([2, 4, 5])
function computeSum(numbers) {
  var sum = 0;
  numbers.forEach(function(number) {
    sum += number;
  });
  return sum;
}
console.log(computeSum([2, 4, 5]));

// # Start with the hash: city_populations = {chi: 2700000}
// # Add populations to the city_populations hash for New York City (8.4 million) and San Francisco (800,000).
// # The result should be: {chi: 2700000, nyc: 8400000, sf: 800000}
// city_populations = {chi: 2700000}
// city_populations[:nyc] = 8400000
// city_populations[:sf] = 800000
// p city_populations
var cityPopulations = {chi: 2700000};
cityPopulations["nyc"] = 8400000;
cityPopulations.sf = 800000;  // same as cityPopulations["sf"]
console.log(cityPopulations);



// # Write a method that prints out every number from 1 to 100. 
function printOneThroughOneHundred() {
  var index = 0;
  while (index <= 100) {
    console.log(index);
    index ++;
  }
}

printOneThroughOneHundred






// # Write a method that prints out every other number from 1 to 100. (That is, 1, 3, 5, 7 … 99).

function printEveryOtherNumber() {
  var index = 0;
  while (index <= 100) {
    if (index % 2 !== 0) {
      console.log(index);
    }
    index++;
  }
}

printEveryOtherNumber




// # Write a method that accepts an array of numbers as a parameter, and counts how many 55’s there are in the array.



function printCountsNumbers(numbers) {
  var count = 0;
  numbers.forEach(function(number) {
    if (number === 55) {
      console.log(number);
      count++;
    }
  });
  console.log(count)
}
 
printCountsNumbers[55, 4, 67, 55, 34, 21, 55]





// # Write a method that accepts an array of strings and returns a new array that has the string “awesomesauce” inserted between every string. 
// # For example, if the initial array is [“a”, “b”, “c”, “d”, “e”], then the returned array should be [“a”, “awesomesauce”, “b”,  “awesomesauce”, “c”,  “awesomesauce”, “d”,  “awesomesauce”, “e”].












// # Start with the hash: item_amounts = {chair: 5, table: 2}
// # Someone just bought two chairs. Change the hash such that the chair amount is 3.
// # The final result should be: {chair: 3, table: 2}







// # Start with the hash: item_amounts = {chair: 5, table: 2}
// # You received 7 desks to sell. Change the hash to include desks.
// # The final result should be: {chair: 5, table: 2, desk: 7}






// # Write a method that accepts a number and returns its factorial.
// # For example, the factorial of 5 is 5 * 4 * 3 * 2 * 1 = 120.









// # Write a method that accepts two arrays of numbers, and prints the sum of every combination of numbers from first and second array. 
// # For example, if the method receives [1, 5, 10] and [100, 500, 1000], the method should print a list: 101, 501, 1001, 105, 505, 1005, 110, 510, 1010].