std::to_string

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

std::string

1) buf std::sprintf(buf, "%d", value)

2) buf std::sprintf(buf, "%ld", value)

3) buf std::sprintf(buf, "%lld", value)

4) buf std::sprintf(buf, "%u", value)

5) buf std::sprintf(buf, "%lu", value)

6) buf std::sprintf(buf, "%llu", value)

7,8) buf std::sprintf(buf, "%f", value)

9) buf std::sprintf(buf, "%Lf", value)

value

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std::string std::bad_alloc

std::to_string
std::cout
std::to_string std::to_string C++17 std::to_chars

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';
}

:

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

to_wstring (C++11)	`wstring` () [edit]
stoulstoull (C++11)(C++11)	() [edit]
stoistolstoll (C++11)(C++11)(C++11)	() [edit]
stofstodstold (C++11)(C++11)(C++11)	() [edit]
to_chars (C++17)	() [edit]

cppreference.com

std::to_string