std::to_string

 

C++

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Standard library headers

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Utilities library

Strings library

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Iterators library

Numerics library

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Regular expressions library(C++11)

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Thread support library(C++11)

Filesystem library(C++17)

Technical Specifications

 

Strings library

Null-terminated strings

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Classes

basic_string

basic_string_view (C++17)

char_traits

 

std::basic_string

Member functions basic_string::basic_string basic_string::operator= basic_string::assign basic_string::get_allocator Element access basic_string::at basic_string::operator[] basic_string::front (C++11) basic_string::back (C++11) basic_string::data basic_string::c_str basic_string::operator basic_string_view (C++17) Iterators basic_string::beginbasic_string::cbegin (C++11) basic_string::endbasic_string::cend (C++11) basic_string::rbeginbasic_string::crbegin (C++11) basic_string::rendbasic_string::crend (C++11) Capacity basic_string::empty basic_string::sizebasic_string::length basic_string::max_size basic_string::reserve basic_string::capacity basic_string::shrink_to_fit (C++11)

Operations basic_string::clear basic_string::insert basic_string::erase basic_string::push_back basic_string::pop_back (C++11) basic_string::append basic_string::operator+= basic_string::compare basic_string::replace basic_string::substr basic_string::copy basic_string::resize basic_string::swap Search basic_string::find basic_string::rfind basic_string::find_first_of basic_string::find_first_not_of basic_string::find_last_of basic_string::find_last_not_of Constants basic_string::npos

Non-member functions operator+ operator==operator!=operator<operator>operator<=operator>= swap(std::basic_string) operator<<operator>> getline stoistolstoll (C++11)(C++11)(C++11) stoulstoull (C++11)(C++11) stofstodstold (C++11)(C++11)(C++11) to_string (C++11) to_wstring (C++11) operator""s (C++14) Helper classes hash<std::string>hash<std::wstring>hash<std::u32string>hash<std::u16string> (C++11)(C++11)(C++11)(C++11)

 

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(longlong value );	(3)	(since C++11)
std::string to_string(unsigned value );	(4)	(since C++11)
std::string to_string(unsignedlong value );	(5)	(since C++11)
std::string to_string(unsignedlonglong 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(longdouble 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

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.

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)
stoulstoull (C++11)(C++11)	converts a string to an unsigned integer (function)
stoistolstoll (C++11)(C++11)(C++11)	converts a string to a signed integer (function)
stofstodstold (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)