C++ Program For Double to String Conversion

Here, we will build a C++ program for double to string conversion using various methods i.e.

1. Using to_string
2. Using stringstream
3. Using sprintf
4. Using lexical_cast

We will keep the same input in all the mentioned approaches and get an output accordingly.

Input:

n = 456321.7651234 

Output: 

string: 456321.7651234  

1. Using to_string 

 In C++, use std::to string to convert a double to a string. The required parameter is a double value, and a string object containing the double value as a sequence of characters is returned.

C++

// C++ Program to demonstrate Double to
// String Conversion using to_string

#include <iostream>
#include <string.h>
using namespace std;

int main()
{

    double n = 456321.7651234;
    string str = to_string(n);
    cout << "String is: " << str;
    return 0;
}

Output

String is: 456321.765123

2. Using stringstream

A double can also be converted into a string in C++ in different ways depending on our requirements using ostringstream.

C++

// C++ Program to demonstrate Double to
// String Conversion using string stream

#include <iostream>
#include <sstream>
#include <string>
using namespace std;

int main()
{
    ostringstream s;
    double n = 2332.43;
    s << n;
    string str = s.str();
    cout << "String is:" << str;
    return 0;
}

Output

String is:2332.43

3. Using sprintf

By specifying the precision in sprintf, we can convert double to string or character array with custom precision. We can use sprintf to add extra text (as required) to the string at the same time.

C++

// C++ Program to demonstrate Double to
// String Conversion using sprintf

#include <cstring>
#include <iostream>
#include <string>
#define Max_Digits 10
using namespace std;

int main()
{
    double N = 1243.3456;
    char str[Max_Digits + sizeof(char)];
    std::sprintf(str, "%f", N);
    std::printf("string is: %s \n", str);

    return 0;
}

Output

string is: 1243.345600 

4. Using lexical_cast

The lexical cast is one of the best ways to convert double to string.

C++

// C++ Program to demonstrate Double to
// String Conversion using lexical_cast

#include <boost/lexical_cast.hpp>
#include <iostream>
#include <string>
using namespace std;

int main()
{
    double n = 432.12;
    string str = boost::lexical_cast<string>(n);
    cout << "string is:" << str;
    return 0;
}

Output

string is:432.12