js-coding-challenges

Challenge 15: Swap two numbers

Write a function that takes two numbers as input and swaps the numbers. For example if inputs are num_1 = 5 and num_2 = 10 the function should return num_1 = 10 and num_2 = 5

Answer 1

function swap(num_1,num_2){
    console.log("Before swapping:\n num_1 = "+num_1+"\n num_2="+num_2)
  var temp = num_1;
      num_1 = num_2;
      num_2 = temp
    console.log("After swapping:\n num_1 = "+num_1+"\n num_2="+num_2)
}

Answer 2

// Declare a function swap that takes num_1 and num_2 as parameters.
function swap(num_1, num_2) {
  // At first print the numbers before swaping
  console.log("Before swapping:\n num_1 = " + num_1 + "\n num_2 = " + num_2);
  num_1 = num_1 + num_2;
  num_2 = num_1 - num_2;
  num_1 = num_1 - num_2;
  // Check the result by printing the output
  console.log("After swapping:\n num_1 = " + num_1 + "\n num_2 = " + num_2);
}

Answer Explanation

Answer 1

This function takes num_1 and num_2 and swaps their values. At first, the value of num_1 is assigned to a variable temp then the value of num_2 is assigned to num_1. Finally the value of temp assigned to num_2. The values are swapped.

Here’s an example of usage of the function:

swap(5,10)
/* 
Before swapping:
num_1 = 5
num_2 = 10
After swapping:
num_1 = 10
num_2 = 5 
*/ 

Answer 2

In this case the swap function takes same number of arguments ie num_1 & num_2. But instead of assigning their values to a third temporary variable, basic maths is used.

swap(30,20)
/*
Then num_1 =30, num_2=20.

num_1 = 30 + 20 = 50
num_2 = 50 - 20 = 30
num_1 = 50 - 30 = 20

We'll get num_1 as 20 and num_2 as 30.
*/

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