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Home Forums CPP scientific computing discussion Assignment 2 (after modul4)


  • Nishant

    August 30, 2023 at 9:40 am

    Hi Baybarskahn,

    Thanks for your question and my apologies for the delayed reply since I was away for the last few days.

    Of course, I’d be happy to explain the behavior you have observing in your output.

    When you are printing double values like 1.0, 0.0, etc., in C++ to a file (or to the console), the default behavior of the output stream (cout or a file stream) is to format the values according to their inherent precision and the way they are represented internally in memory.

    A double in C++ is a floating-point data type that can hold decimal values with a higher degree of precision than integers. Internally, floating-point numbers are stored using a format called IEEE 754, which represents the number in a binary format with a sign bit, an exponent, and a fraction (or mantissa).

    When you print a double value, the stream’s formatting settings dictate how many decimal places will be displayed. If the value is a whole number (e.g., 1.0, 0.0), the default formatting is such that the decimal part is not displayed, making it look like an integer. This is often done for aesthetic reasons, as displaying trailing “.0” for whole numbers might be considered unnecessary clutter.

    If you want to ensure that the decimal part is always displayed, regardless of whether it’s “.0” or not, you can use stream manipulators to control the formatting. Here’s an example:

    #include <iostream>
    #include <iomanip> // Include this for formatting manipulators

    int main() {
    double value = 1.0;

    std::cout << std::fixed << std::setprecision(1); // Set precision to 1 decimal place
    std::cout << value << std::endl;

    return 0;

    In this example, std::fixed ensures that the number is printed in fixed-point notation (decimal), and std::setprecision(1) sets the number of decimal places to be displayed to 1.

    Remember that the behavior might also vary depending on the compiler, compiler settings, and the platform you are running your code on. But generally, the above explanation holds for most standard C++ environments.

  • baybarskahn

    August 30, 2023 at 12:30 pm

    Thanks a lot for detailed answer Mr. Soni.

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