JavaScript Program to Check if Two Numbers have Same Last Digit
Last Updated :
13 Jun, 2024
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In this article, we will discuss how to check if two numbers have the same last digit in JavaScript. Checking the last digit of a number is a common requirement in programming tasks, and it can be useful in various scenarios. We will explore an approach using JavaScript to accomplish this task.
Methods to Check Both Numbers have the Same Last Digit
Table of Content
We will explore every approach for checking if the Numbers Have the Same Last Digit, along with understanding their basic implementations.
Approach 1: Using the Modulus Operator (%)
- Take the modulus (%) of both numbers with 10 to extract their last digits.
- Compare the last digits using the ===.
- Return
trueif the last digits are the same, otherwise returnfalse.
Example: In this example we are following above mentioned approach.
// Define function to check last digit of number
function haveSameLastDigit(num1, num2) {
// Getting last digit using % operator
const lastDigit1 = num1 % 10;
const lastDigit2 = num2 % 10;
// Return if last digits are same or not
return lastDigit1 === lastDigit2;
}
const number1 = 123;
const number2 = 456;
// Calling function with arguements
const result = haveSameLastDigit(number1, number2);
// Giving output
console.log(result);
Output
false
Approach 2: Converting Numbers to Strings
- Convert both numbers to strings using the
toString()method. - Get the last character (digit) of each string using the
slice()method. - Compare the last digits using the ===.
- Return
trueif the last digits are the same, otherwise returnfalse.
Syntax:
string.slice(startIndex, endIndex);Example:
// Define function to check if two numbers have the same last digit
function haveSameLastDigit(num1, num2) {
// Getting last digit using "toString" and "slice" methods
const lastDigit1 = num1.toString().slice(-1);
const lastDigit2 = num2.toString().slice(-1);
// Return if last digits are same or not
return lastDigit1 === lastDigit2;
}
// Define two numbers
const number1 = 123;
const number2 = 453;
// Calling function with arguments
const result = haveSameLastDigit(number1, number2);
// Output the result
console.log(result);
Output
true
Approach 3: Using the Array of Digits
- Create an array of digits for each number using the spread operator.
- Get the last digit of each array using the array index.
- Compare the last digits using the ===.
- Return
trueif the last digits are the same, otherwise returnfalse.
Syntax:
// Spread operator
[...iterable]
Example:
// Define function to check last digit of number
function haveSameLastDigit(num1, num2) {
// Converting number to string
const digits1 = [...num1.toString()];
const digits2 = [...num2.toString()];
// Getting last character of string
const lastDigit1 = digits1[digits1.length - 1];
const lastDigit2 = digits2[digits2.length - 1];
// Return if last digits are same or not
return lastDigit1 === lastDigit2;
}
const number1 = 123;
const number2 = 453;
// Calling function with arguements
const result = haveSameLastDigit(number1, number2);
// Giving output
console.log(result);
Output
true
Approach 4: Using the Bitwise AND Operator
- The Bitwise AND operator
&to perform a bitwise AND operation between the numbers and 1 (num1 & 1andnum2 & 1). - The result will be 1 if the last bit (last digit) of both numbers is the same, and 0 otherwise.
- Then, we compare the results using the strict equality operator
===to check if they are equal. - If they are equal, it means the numbers have the same last digit.
Syntax:
firstNum=num&1function hasSameLastDigit(num1, num2) {
// Get the last bit of num1
const lastDigit1 = num1 & 1;
// Get the last bit of num2
const lastDigit2 = num2 & 1;
return lastDigit1 === lastDigit2;
}
// Example usage:
const number1 = 123;
const number2 = 453;
const result = hasSameLastDigit(number1, number2);
console.log(result); // Output: false
Output
true
Approach 5: Using Math.floor() Method
This method involves a combination of floor division and multiplication to isolate the last digit of each number. The steps are as follows:
- Divide each number by 10 and take the integer part (floor division) to remove the last digit.
- Multiply the result of the division by 10 to get a number ending in zero.
- Subtract this number from the original number to isolate the last digit.
- Compare the isolated last digits using the strict equality operator (===).
- Return true if the last digits are the same, otherwise return false.
Example:
// Define function to check if two numbers have the same last digit
function haveSameLastDigit(num1, num2) {
// Isolate the last digit using floor division and multiplication
const lastDigit1 = num1 - Math.floor(num1 / 10) * 10;
const lastDigit2 = num2 - Math.floor(num2 / 10) * 10;
// Return if last digits are same or not
return lastDigit1 === lastDigit2;
}
// Define two numbers
const number1 = 123;
const number2 = 453;
// Calling function with arguments
const result = haveSameLastDigit(number1, number2);
// Output the result
console.log(result);
Output
true
