C++ question How to convert double to string

C++ question How to convert double to string? if there is a double number for example 10, I want double 10 to converts to string 10. I used to_string() and the double number become a 10.000000 string.

The Correct Answer and Explanation is:

To convert a double to a string in C++ without adding unnecessary decimal places like .000000, you should use output string streams (std::ostringstream) instead of std::to_string(). Here’s the correct approach:

✅ Example:

cppCopyEdit#include <iostream>
#include <sstream>
#include <string>

std::string doubleToString(double value) {
    std::ostringstream out;
    out << value;
    return out.str();
}

int main() {
    double num = 10.0;
    std::string result = doubleToString(num);
    std::cout << "Converted string: " << result << std::endl;
    return 0;
}

✅ Output:

csharpCopyEditConverted string: 10

✅ Explanation :

In C++, the standard function std::to_string() is often used to convert numeric values to strings. However, when used with floating-point types like double, it always produces a fixed format string with six digits after the decimal point. For example, std::to_string(10.0) results in "10.000000". This is often not desirable when a cleaner, more human-readable format is needed.

To avoid this issue and generate a more natural string representation, you can use the std::ostringstream class from the <sstream> header. It allows for more control over how numbers are formatted during conversion.

In the provided code, an ostringstream object is created, and the double value is inserted into it using the insertion operator (<<). The stream automatically formats the number based on its value. If the number has no fractional component, it omits the decimal point and trailing zeros. The str() method then retrieves the string from the stream.

This method is both cleaner and more flexible. If you ever need to customize the format further, such as setting precision or forcing fixed or scientific notation, ostringstream allows you to do that using stream manipulators like std::fixed, std::setprecision(), and std::scientific.

Overall, using std::ostringstream is the preferred way to convert double to string in C++ when you want the output to match the natural appearance of the number rather than a fixed precision format.