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operator+,-,*,/,%,&,|,^,<<,>>,&&,|| (std::valarray)

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C++
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std::valarray
Member functions
Non-member functions
operator* operator/ operator% operator+ operator- operator^ operator& operator| operator<< operator>> operator&& operator||

Helper classes
Deduction guides (C++17)
定义于头文件 <valarray>
template < class T >

std:: valarray < T > operator + ( const std:: valarray < T > & lhs, const std:: valarray < T > & rhs ) ;
template < class T >
std:: valarray < T > operator - ( const std:: valarray < T > & lhs, const std:: valarray < T > & rhs ) ;
template < class T >
std:: valarray < T > operator * ( const std:: valarray < T > & lhs, const std:: valarray < T > & rhs ) ;
template < class T >
std:: valarray < T > operator / ( const std:: valarray < T > & lhs, const std:: valarray < T > & rhs ) ;
template < class T >
std:: valarray < T > operator % ( const std:: valarray < T > & lhs, const std:: valarray < T > & rhs ) ;
template < class T >
std:: valarray < T > operator & ( const std:: valarray < T > & lhs, const std:: valarray < T > & rhs ) ;
template < class T >
std:: valarray < T > operator | ( const std:: valarray < T > & lhs, const std:: valarray < T > & rhs ) ;
template < class T >
std:: valarray < T > operator ^ ( const std:: valarray < T > & lhs, const std:: valarray < T > & rhs ) ;
template < class T >
std:: valarray < T > operator << ( const std:: valarray < T > & lhs, const std:: valarray < T > & rhs ) ;
template < class T >
std:: valarray < T > operator >> ( const std:: valarray < T > & lhs, const std:: valarray < T > & rhs ) ;
template < class T >
std:: valarray < bool > operator && ( const std:: valarray < T > & lhs, const std:: valarray < T > & rhs ) ;
template < class T >

std:: valarray < bool > operator || ( const std:: valarray < T > & lhs, const std:: valarray < T > & rhs ) ;
(1)
template < class T >

std:: valarray < T > operator + ( const typename std:: valarray < T > :: value_type & val,
const std:: valarray < T > & rhs ) ;
template < class T >
std:: valarray < T > operator - ( const typename std:: valarray < T > :: value_type & val,
const std:: valarray < T > & rhs ) ;
template < class T >
std:: valarray < T > operator * ( const typename std:: valarray < T > :: value_type & val,
const std:: valarray < T > & rhs ) ;
template < class T >
std:: valarray < T > operator / ( const typename std:: valarray < T > :: value_type & val,
const std:: valarray < T > & rhs ) ;
template < class T >
std:: valarray < T > operator % ( const typename std:: valarray < T > :: value_type & val,
const std:: valarray < T > & rhs ) ;
template < class T >
std:: valarray < T > operator & ( const typename std:: valarray < T > :: value_type & val,
const std:: valarray < T > & rhs ) ;
template < class T >
std:: valarray < T > operator | ( const typename std:: valarray < T > :: value_type & val,
const std:: valarray < T > & rhs ) ;
template < class T >
std:: valarray < T > operator ^ ( const typename std:: valarray < T > :: value_type & val,
const std:: valarray < T > & rhs ) ;
template < class T >
std:: valarray < T > operator << ( const typename std:: valarray < T > :: value_type & val,
const std:: valarray < T > & rhs ) ;
template < class T >
std:: valarray < T > operator >> ( const typename std:: valarray < T > :: value_type & val,
const std:: valarray < T > & rhs ) ;
template < class T >
std:: valarray < bool > operator && ( const typename std:: valarray < T > :: value_type & val,
const std:: valarray < T > & rhs ) ;
template < class T >
std:: valarray < bool > operator || ( const typename std:: valarray < T > :: value_type & val,

const std:: valarray < T > & rhs ) ;
(2)
template < class T >

std:: valarray < T > operator + ( const std:: valarray < T > & lhs,
const typename std:: valarray < T > :: value_type & val ) ;
template < class T >
std:: valarray < T > operator - ( const std:: valarray < T > & lhs,
const typename std:: valarray < T > :: value_type & val ) ;
template < class T >
std:: valarray < T > operator * ( const std:: valarray < T > & lhs,
const typename std:: valarray < T > :: value_type & val ) ;
template < class T >
std:: valarray < T > operator / ( const std:: valarray < T > & lhs,
const typename std:: valarray < T > :: value_type & val ) ;
template < class T >
std:: valarray < T > operator % ( const std:: valarray < T > & lhs,
const typename std:: valarray < T > :: value_type & val ) ;
template < class T >
std:: valarray < T > operator & ( const std:: valarray < T > & lhs,
const typename std:: valarray < T > :: value_type & val ) ;
template < class T >
std:: valarray < T > operator | ( const std:: valarray < T > & lhs,
const typename std:: valarray < T > :: value_type & val ) ;
template < class T >
std:: valarray < T > operator ^ ( const std:: valarray < T > & lhs,
const typename std:: valarray < T > :: value_type & val ) ;
template < class T >
std:: valarray < T > operator << ( const std:: valarray < T > & lhs,
const typename std:: valarray < T > :: value_type & val ) ;
template < class T >
std:: valarray < T > operator >> ( const std:: valarray < T > & lhs,
const typename std:: valarray < T > :: value_type & val ) ;
template < class T >
std:: valarray < bool > operator && ( const std:: valarray < T > & lhs,
const typename std:: valarray < T > :: value_type & val ) ;
template < class T >
std:: valarray < bool > operator || ( const std:: valarray < T > & lhs,

const typename std:: valarray < T > :: value_type & val ) ;
(3)

对两个 valarray 的每个元素，或一个 valarray 与一个值应用二元运算符。

1) 运算符作用于相同大小的valarray，并返回与参数大小相同的valarray，其中包含对两个参数每个元素应用操作后的结果。
2,3) 对 valarray 的每个元素与标量之间应用该运算符。

目录

参数

rhs - 数值数组
lhs - 数值数组
val - 类型为 T 的值

返回值

一个与参数大小相同的 valarray。

注意

当两个参数是大小不同的 valarray 时，行为是未定义的。

该函数的实现可以具有不同于 std::valarray 的返回类型。在这种情况下，替换类型需具备以下特性：

示例

求解多个 二次方程 的实根。

运行此代码 
#include <cstddef>
#include <iostream>
#include <valarray>
int main()
{
    std::valarray<double> a(1, 8);
    std::valarray<double> b{1, 2, 3, 4, 5, 6, 7, 8};
    std::valarray<double> c = -b;
    // literals must also be of type T until LWG3074 (double in this case)
    std::valarray<double> d = std::sqrt(b * b - 4.0 * a * c);
    std::valarray<double> x1 = 2.0 * c / (-b + d);
    std::valarray<double> x2 = 2.0 * c / (-b - d);
    std::cout << "quadratic equation:  root 1:    root 2:   b: c:\n";
    for (std::size_t i = 0; i < a.size(); ++i)
        std::cout << a[i] << "\u00B7x\u00B2 + " << b[i] << "\u00B7x + "
                  << c[i] << " = 0  " << std::fixed << x1[i]
                  << "  " << x2[i] << std::defaultfloat
                  << "  " << -x1[i] - x2[i]
                  << "  " << x1[i] * x2[i] << '\n';
}

输出： 

quadratic equation:  root 1:    root 2:   b: c:
1·x² + 1·x + -1 = 0  -1.618034  0.618034  1  -1
1·x² + 2·x + -2 = 0  -2.732051  0.732051  2  -2
1·x² + 3·x + -3 = 0  -3.791288  0.791288  3  -3
1·x² + 4·x + -4 = 0  -4.828427  0.828427  4  -4
1·x² + 5·x + -5 = 0  -5.854102  0.854102  5  -5
1·x² + 6·x + -6 = 0  -6.872983  0.872983  6  -6
1·x² + 7·x + -7 = 0  -7.887482  0.887482  7  -7
1·x² + 8·x + -8 = 0  -8.898979  0.898979  8  -8

缺陷报告

以下行为变更缺陷报告被追溯应用于先前发布的 C++ 标准。

DR 适用版本 发布行为 正确行为
LWG 3074 C++98 T 同时从标量和 valarray 推导 (2,3) ，不允许混合类型调用 仅从 valarray 推导 T

另请参阅

对 valarray 的每个元素应用一元算术运算符
(公开成员函数)
对 valarray 的每个元素应用复合赋值运算符
(公开成员函数)