std::to_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) |
将数值转换为std::string...
1%29将有符号的十进制整数转换为具有以下内容的字符串std::sprintf(buf, "%d", value)会产生足够大的buf...
2%29将有符号的十进制整数转换为具有以下内容的字符串std::sprintf(buf, "%ld", value)会产生足够大的buf...
3%29将有符号的十进制整数转换为具有以下内容的字符串std::sprintf(buf, "%lld", value)会产生足够大的buf...
4%29将无符号十进制整数转换为内容与std::sprintf(buf, "%u", value)会产生足够大的buf...
5%29将无符号十进制整数转换为内容与std::sprintf(buf, "%lu", value)会产生足够大的buf...
6%29将无符号十进制整数转换为内容与std::sprintf(buf, "%llu", value)会产生足够大的buf...
7，8%29将浮点值转换为具有与以下内容相同内容的字符串std::sprintf(buf, "%f", value)会产生足够大的buf...
9%29将浮点值转换为与以下内容相同的字符串std::sprintf(buf, "%Lf", value)会产生足够大的buf...
参数
value | - | a numeric value to convert |
|---|
返回值
保存转换值的字符串。
注记
- 带浮点类型
std::to_string可能会产生意外的结果，因为返回字符串中的有效位数可以为零，请参见示例。
- 返回值可能与
std::cout默认情况下打印，请参见示例。
例
二次
#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';
}二次
产出：
二次
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: 123456789.000000二次
另见
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) |
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