| 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.
Notes
std::to_string may yield unexpected results when used with floating point types and the return values may be substantially different from what std::cout would print, see the example.
Example
#include <iostream>
#include <string>
int main()
{
double f = 23.43;
double f2 = 1e-9;
double f3 = 1e40;
double f4 = 1e-40;
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::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';
}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
See also
| (C++11) | converts an integral or floating point value to wstring (function) |
| (C++11)(C++11) | converts a string to an unsigned integer (function) |
| (C++11)(C++11)(C++11) | converts a string to a signed integer (function) |
| (C++11)(C++11)(C++11) | converts a string to a floating point value (function) |
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