Converting Double to String in C++14: Methods Explained

double to string in C++ 14

In C++14, you can convert a double to a std::string using the std::to_string function, which is part of the standard library. Here's a simple example to demonstrate this:

#include <iostream>
#include <string>

int main() {
    double myDouble = 3.14159;
    std::string myString = std::to_string(myDouble);

    std::cout << "The double as a string is: " << myString << std::endl;

    return 0;
}

In this example:

• We include the necessary headers: <iostream> for input/output operations and <string> for the std::string class.
• We declare a double variable myDouble and initialize it with a value.
• We use std::to_string to convert the double to a std::string and store the result in myString.
• Finally, we print the resulting string.

The std::to_string function is straightforward and convenient for converting numeric values to strings. However, it may not provide the level of control over formatting that you might need in some cases. If you need more control over the formatting (e.g., specifying the number of decimal places), you can use string streams:

#include <iostream>
#include <sstream>
#include <string>
#include <iomanip>

int main() {
    double myDouble = 3.14159;
    std::ostringstream oss;
    oss << std::fixed << std::setprecision(2) << myDouble;
    std::string myString = oss.str();

    std::cout << "The double as a string with 2 decimal places is: " << myString << std::endl;

    return 0;
}

In this example:

• We include the <sstream> and <iomanip> headers for string stream and formatting utilities.
• We use an std::ostringstream object to build the string.
• We use manipulators like std::fixed and std::setprecision to control the formatting of the double.
• We convert the contents of the stream to a std::string using the str() method of the std::ostringstream object.

This approach gives you more control over the formatting of the output string.