added log code for counting digits

math/finding_number_of_digits_in_a_number.cpp

@@ -9,7 +9,7 @@
  * 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).
+ * numbers (not integers) code for that also included (count_digits).
  * 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.
@@ -17,10 +17,12 @@
 
 #include <cassert>   /// for assert
 #include <iostream>  /// for IO operations
+#include <cmath>    /// for log calculation
 
 /**
  * @brief The main function that checks
  * the number of digits in a number.
+ * TC : O(number of digits)
  * @param n the number to check its digits
  * @returns the digits count
  */
@@ -40,6 +42,29 @@ uint64_t finding_number_of_digits_in_a_number(uint64_t n) {
     return count;
 }
 
+/**
+ * @brief This function finds the number of digits
+ * in constant time
+ * TC :O(1)
+ * @param n the number to check its digits
+ * @returns the digits count
+ */
+uint64_t count_digits(uint64_t n) {
+    // to handle the negative numbers 
+    if(n < 0){
+        n = -n;
+    }
+    
+    // log(0) is undefined
+    else if(n == 0){
+    //handling the value 0
+     return 0;    
+    }
+    uint64_t count = floor(log10(n) + 1);
+
+    return count;
+}
+
 /**
  * @brief Self-test implementations
  * @returns void
@@ -52,10 +77,18 @@ static void test() {
     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);
+    assert(count_digits(5492) == 4);
+    assert(count_digits(-0) == 0);
+    assert(count_digits(10000) == 5);
+    assert(count_digits(9) == 1);
+    assert(count_digits(100000) == 6);
+    assert(count_digits(13) == 2);
+    assert(count_digits(564) == 3);
 
     std::cout << "All tests have successfully passed!\n";
 }
 
+
 /**
  * @brief Main function
  * @returns 0 on exit