feat: Finding no. of digits in a Number (#1497)

* Finding no. of digits in a Number

* Initialize n

* Initialize n as int

* Changes done

* Changes done with codes by adding more comments

* Changes done with codes by adding name as md

* Modified comments

* add void

* remove void & update comments

* Set some changes to pass Awesome CI Workflow

* add return 0 & file name in lower case

* Changes done..

* Update finding_number_of_Digits_in_a_Number.cpp

* Update finding_number_of_Digits_in_a_Number.cpp

* Update finding_number_of_Digits_in_a_Number.cpp

* formatting filenames 0ec45e33

* updating DIRECTORY.md

* clang-format and clang-tidy fixes for 0ec45e33

* clang-format and clang-tidy fixes for 9c0a437e

* updating DIRECTORY.md

* Wrote test, needs review

* [fix/docs]: Fix tests/code and add documentation

Co-authored-by: David Leal <halfpacho@gmail.com>
Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>

DIRECTORY.md

@@ -170,6 +170,7 @@
   * [Fibonacci Large](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/math/fibonacci_large.cpp)
   * [Fibonacci Matrix Exponentiation](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/math/fibonacci_matrix_exponentiation.cpp)
   * [Fibonacci Sum](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/math/fibonacci_sum.cpp)
+  * [Finding Number Of Digits In A Number](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/math/finding_number_of_digits_in_a_number.cpp)
   * [Gcd Iterative Euclidean](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/math/gcd_iterative_euclidean.cpp)
   * [Gcd Of N Numbers](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/math/gcd_of_n_numbers.cpp)
   * [Gcd Recursive Euclidean](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/math/gcd_recursive_euclidean.cpp)

math/finding_number_of_digits_in_a_number.cpp

@@ -0,0 +1,66 @@
+/**
+ * @author [aminos 🇮🇳](https://github.com/amino19)
+ * @file
+ *
+ * @brief [Program to count digits
+ * in an
+ * integer](https://www.geeksforgeeks.org/program-count-digits-integer-3-different-methods)
+ * @details It is a very basic math of finding number of digits in a given
+ * number i.e, we can use it by inputting values whether it can be a
+ * positive/negative value, let's say: an integer. There is also a second
+ * method: by using "K = floor(log10(N) + 1)", but it's only applicable for
+ * numbers (not integers).
+ * For more details, refer to the
+ * [Algorithms-Explanation](https://github.com/TheAlgorithms/Algorithms-Explanation/blob/master/en/Basic%20Math/Finding
+ * the number of digits in a number.md) repository.
+ */
+
+#include <cassert>   /// for assert
+#include <iostream>  /// for IO operations
+
+/**
+ * @brief The main function that checks
+ * the number of digits in a number.
+ * @param n the number to check its digits
+ * @returns the digits count
+ */
+uint64_t finding_number_of_digits_in_a_number(uint64_t n) {
+    uint64_t count = 0;  ///< the variable used for the digits count
+
+    // iterate until `n` becomes 0
+    // remove last digit from `n` in each iteration
+    // increase `count` by 1 in each iteration
+    while (n != 0) {
+        // we can also use `n = n / 10`
+        n /= 10;
+        // each time the loop is running, `count` will be incremented by 1.
+        ++count;
+    }
+
+    return count;
+}
+
+/**
+ * @brief Self-test implementations
+ * @returns void
+ */
+static void test() {
+    assert(finding_number_of_digits_in_a_number(5492) == 4);
+    assert(finding_number_of_digits_in_a_number(-0) == 0);
+    assert(finding_number_of_digits_in_a_number(10000) == 5);
+    assert(finding_number_of_digits_in_a_number(9) == 1);
+    assert(finding_number_of_digits_in_a_number(100000) == 6);
+    assert(finding_number_of_digits_in_a_number(13) == 2);
+    assert(finding_number_of_digits_in_a_number(564) == 3);
+
+    std::cout << "All tests have successfully passed!\n";
+}
+
+/**
+ * @brief Main function
+ * @returns 0 on exit
+ */
+int main() {
+    test();  // run self-test implementations
+    return 0;
+}

search/floyd_cycle_detection_algo.cpp

@@ -35,12 +35,14 @@ namespace cycle_detection {
  */
 template <typename T>
 int32_t duplicateNumber(const std::vector<T> &in_arr, const uint32_t &n) {
-    if (n == 0 || n == 1) {  // to find duplicate in an array its size should be atleast 2
+    if (n == 0 ||
+        n == 1) {  // to find duplicate in an array its size should be atleast 2
         return -1;
     }
     uint32_t tortoise = in_arr[0];  // variable tortoise is used for the longer
                                     // jumps in the array
-    uint32_t hare = in_arr[0];  // variable hare is used for shorter jumps in the array
+    uint32_t hare =
+        in_arr[0];  // variable hare is used for shorter jumps in the array
     do {
         tortoise = in_arr[tortoise];
         hare = in_arr[in_arr[hare]];

sorting/dnf_sort.cpp

@@ -1,7 +1,8 @@
 /**
  * @file
  * @brief Implementation of the [DNF
- * sort](https://www.geeksforgeeks.org/sort-an-array-of-0s-1s-and-2s/) implementation
+ * sort](https://www.geeksforgeeks.org/sort-an-array-of-0s-1s-and-2s/)
+ * implementation
  * @details
  * C++ program to sort an array with 0, 1 and 2 in a single pass(DNF sort).
  * Since one traversal of the array is there hence it works in O(n) time
@@ -22,7 +23,8 @@ namespace sorting {
 /**
  * @namespace dnf_sort
  * @brief Functions for the [DNF
- * sort](https://en.wikipedia.org/wiki/Dutch_national_flag_problem) implementation
+ * sort](https://en.wikipedia.org/wiki/Dutch_national_flag_problem)
+ * implementation
  */
 namespace dnf_sort {
 /**