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JavaScript: Check an integer is Repdigit number or not

JavaScript Math: Exercise-80 with Solution

Check Repdigit Number

Write a JavaScript program to check whether a given integer is a Repdigit or not.

From Wikipedia -
In recreational mathematics, a repdigit or sometimes monodigit is a natural number composed of repeated instances of the same digit in a positional number system (often implicitly decimal). The word is a portmanteau of repeated and digit. Examples are 11, 666, 4444, and 999999.

Test Data:
(11) -> true
(66) -> true
(336) -> false
(444) -> true
(1151) -> false

Sample Solution:

JavaScript Code:

/**
 * Function to check if a number is a Repdigit.
 * @param {number} n - The input number.
 * @returns {boolean} - True if the number is a Repdigit, otherwise false.
 */
function test(n) {
    // Convert the number to a string and create a set to count unique digits
    return new Set('' + n).size === 1;
}

// Test cases
// Assign value to n
n = 11;
// Print the value of n
console.log("n = " + n);
// Check if the said number is Repdigit
console.log("Check the said number is Repdigit: " + test(n));
// Repeat the above steps for different values of n
n = 66;
console.log("n = " + n);
console.log("Check the said number is Repdigit: " + test(n));
n = 336;
console.log("n = " + n);
console.log("Check the said number is Repdigit: " + test(n));
n = 444;
console.log("n = " + n);
console.log("Check the said number is Repdigit: " + test(n));
n = 1151;
console.log("n = " + n);
console.log("Check the said number is Repdigit: " + test(n));

Output:

n = 11
Check the said number is Repdigit: true
n = 66
Check the said number is Repdigit: true
n = 336
Check the said number is Repdigit: false
n = 444
Check the said number is Repdigit: true
n = 1151
Check the said number is Repdigit: false

Flowchart:

JavaScript: Check an integer is Repdigit number or not.

Live Demo:

See the Pen javascript-math-exercise-80 by w3resource (@w3resource) on CodePen.


For more Practice: Solve these Related Problems:

  • Write a JavaScript function that checks whether a number is a repdigit by converting it to a string and comparing all digits.
  • Write a JavaScript function that iterates through the digits of a number and verifies if all digits match the first digit.
  • Write a JavaScript function that uses a regular expression to test if a number consists of repeated digits.
  • Write a JavaScript function that handles single-digit numbers and returns true as they are trivially repdigits.

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