hwo to calculate the number of digits using log in c++

#include <iostream>
#include <cmath>

int main() {
    long long num;
    std::cout << "Enter a number: ";
    std::cin >> num;

    int digits = (int)log10(num) + 1;

    std::cout << "Number of digits: " << digits << std::endl;

    return 0;
}

Explanation:

1. Include Necessary Libraries: #include <iostream> for input/output and #include <cmath> for mathematical functions.

2. Declare Variables: long long num; declares a variable num of type long long to store the user input number.

3. User Input: std::cout << "Enter a number: "; prompts the user to enter a number, and std::cin >> num; reads the input number and stores it in the variable num.

4. Calculate Number of Digits: int digits = (int)log10(num) + 1;

   • log10(num) calculates the logarithm base 10 of the input number num.
   • (int) casts the result to an integer, truncating the decimal part.
   • + 1 adds 1 to the calculated logarithm because the logarithm function returns the power to which the base (10 in this case) must be raised to obtain the input number. Adding 1 accounts for the actual count of digits.
   • The result is stored in the variable digits.

5. Output the Result: std::cout << "Number of digits: " << digits << std::endl; displays the number of digits in the entered number.

6. Return Statement: return 0; ends the main() function execution, indicating successful program execution.