decising how many numbers after comma c++

To determine the number of digits after the decimal point in C++, you can use the modulus operator % and a loop. Here are the steps to achieve this:

1. Initialize a variable number with the value for which you want to determine the number of digits after the decimal point.
2. Multiply number by 10 until it becomes an integer. This will shift the decimal point to the right.
3. Take the modulus (%) of the resulting number with 10. This will give you the digit after the decimal point.
4. Increment a counter variable for each digit obtained from the modulus operation.
5. Repeat steps 2-4 until the number becomes zero.
6. The final value of the counter variable will give you the number of digits after the decimal point.

Here's an example code snippet that implements these steps:

#include <iostream>

int main() {
    double number = 3.14159;  // Example number

    int counter = 0;
    while (number != 0) {
        number *= 10;
        int digit = static_cast<int>(number) % 10;
        counter++;
        number -= digit;
        number /= 10;
    }

    std::cout << "Number of digits after the decimal point: " << counter << std::endl;

    return 0;
}

In this example, the variable number is initialized with the value 3.14159. The while loop is used to shift the decimal point to the right by multiplying number by 10. The modulus operation is then performed to extract the digit after the decimal point, and the counter variable is incremented. Finally, the resulting number is updated by subtracting the extracted digit and dividing by 10. The loop continues until the number becomes zero. The final value of the counter variable is then printed, which represents the number of digits after the decimal point in the original number.