# std::to_string

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< cpp‎ | string‎ | basic string

Defined in header `<string>` |  |
std::string to_string( int value ); | (1) | (since C++11)
std::string to_string( long value ); | (2) | (since C++11)
std::string to_string( long long value ); | (3) | (since C++11)
std::string to_string( unsigned value ); | (4) | (since C++11)
std::string to_string( unsigned long value ); | (5) | (since C++11)
std::string to_string( unsigned long long value ); | (6) | (since C++11)
std::string to_string( float value ); | (7) | (since C++11)
std::string to_string( double value ); | (8) | (since C++11)
std::string to_string( long double value ); | (9) | (since C++11)

Converts a numeric value to std::string.

1) Converts a signed decimal integer to a string with the same content as what std::sprintf(buf, "%d", value) would produce for sufficiently large `buf`.
2) Converts a signed decimal integer to a string with the same content as what std::sprintf(buf, "%ld", value) would produce for sufficiently large `buf`.
3) Converts a signed decimal integer to a string with the same content as what std::sprintf(buf, "%lld", value) would produce for sufficiently large `buf`.
4) Converts an unsigned decimal integer to a string with the same content as what std::sprintf(buf, "%u", value) would produce for sufficiently large `buf`.
5) Converts an unsigned decimal integer to a string with the same content as what std::sprintf(buf, "%lu", value) would produce for sufficiently large `buf`.
6) Converts an unsigned decimal integer to a string with the same content as what std::sprintf(buf, "%llu", value) would produce for sufficiently large `buf`.
7,8) Converts a floating point value to a string with the same content as what std::sprintf(buf, "%f", value) would produce for sufficiently large `buf`.
9) Converts a floating point value to a string with the same content as what std::sprintf(buf, "%Lf", value) would produce for sufficiently large `buf`.

### Parameters

value | - | a numeric value to convert

### Return value

a string holding the converted value

### Exceptions

May throw std::bad_alloc from the std::string constructor.

### Notes

- With floating point types `std::to_string` may yield unexpected results as the number of significant digits in the returned string can be zero, see the example.
- The return value may differ significantly from what `std::cout` prints by default, see the example.
- `std::to_string` relies on the current locale for formatting purposes, and therefore concurrent calls to `std::to_string` from multiple threads may result in partial serialization of calls. C++17 provides `std::to_chars` as a higher-performance locale-independent alternative.

### Example

Run this code

    #include <iostream>
    #include <string>

    int main()
    {
        double f = 23.43;
        double f2 = 1e-9;
        double f3 = 1e40;
        double f4 = 1e-40;
        double f5 = 123456789;
        std::string f_str = std::to_string(f);
        std::string f_str2 = std::to_string(f2); // Note: returns "0.000000"
        std::string f_str3 = std::to_string(f3); // Note: Does not return "1e+40".
        std::string f_str4 = std::to_string(f4); // Note: returns "0.000000"
        std::string f_str5 = std::to_string(f5);
        std::cout << "std::cout: " << f << '\n'
                  << "to_string: " << f_str  << "\n\n"
                  << "std::cout: " << f2 << '\n'
                  << "to_string: " << f_str2 << "\n\n"
                  << "std::cout: " << f3 << '\n'
                  << "to_string: " << f_str3 << "\n\n"
                  << "std::cout: " << f4 << '\n'
                  << "to_string: " << f_str4 << "\n\n"
                  << "std::cout: " << f5 << '\n'
                  << "to_string: " << f_str5 << '\n';
    }

Output:

    std::cout: 23.43
    to_string: 23.430000

    std::cout: 1e-09
    to_string: 0.000000

    std::cout: 1e+40
    to_string: 10000000000000000303786028427003666890752.000000

    std::cout: 1e-40
    to_string: 0.000000

    std::cout: 1.23457e+08
    to_string: 123456789.000000

### See also

to_wstring (C++11) | converts an integral or floating point value to `wstring` (function)
stoul stoull (C++11)(C++11) | converts a string to an unsigned integer (function)
stoi stol stoll (C++11)(C++11)(C++11) | converts a string to a signed integer (function)
stof stod stold (C++11)(C++11)(C++11) | converts a string to a floating point value (function)
to_chars (C++17) | converts an integer or floating-point value to a character sequence (function)

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