std::dec
Defined in header <ios> | | |
|---|---|---|
std::ios_base& dec( std::ios_base& str ); | (1) | |
std::ios_base& hex( std::ios_base& str ); | (2) | |
std::ios_base& oct( std::ios_base& str ); | (3) | |
修改整数I/O的默认数字基。
1%29设置basefield溪流str到dec好像通过打电话str.setf(std::ios_base::dec,std::ios_base::basefield)...
2%29设置basefield溪流str到hex好像通过打电话str.setf(std::ios_base::hex,std::ios_base::basefield)...
3%29设置basefield溪流str到oct好像通过打电话str.setf(std::ios_base::oct,std::ios_base::basefield)...
这是一个I/O操作器。可以用表达式调用它，如out << std::hex对任何out类型std::basic_ostream或使用表达式，如in >> std::hex对任何in类型std::basic_istream...
参数
str | - | reference to I/O stream |
|---|
返回值
str%28操作后对流的引用%29。
例
二次
#include <iostream>
#include <sstream>
int main()
{
std::cout << "The number 42 in octal: " << std::oct << 42 << '\n'
<< "The number 42 in decimal: " << std::dec << 42 << '\n'
<< "The number 42 in hex: " << std::hex << 42 << '\n';
int n;
std::istringstream("2A") >> std::hex >> n;
std::cout << std::dec << "Parsing \"2A\" as hex gives " << n << '\n';
}二次
产出：
二次
The number 42 in octal: 52
The number 42 in decimal: 42
The number 42 in hex: 2a
Parsing "2A" as hex gives 42二次
另见
setbase | changes the base used for integer I/O (function) |
|---|---|
showbasenoshowbase | controls whether prefix is used to indicate numeric base (function) |
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