[英]error: cannot bind ‘std::ostream {aka std::basic_ostream<char>}’ lvalue to ‘std::basic_ostream<char>&&’
您好everonye，甚至我在这里找到了有关此问题的许多答案，一个答案根本无法解释我事情如何无法解决所有问题。
所以我的问题是，当我尝试实现运算符<<作为内联方法时，我遇到了一个名为Matrix的类，出现以下错误
error: cannot bind ‘std::ostream {aka std::basic_ostream<char>}’ lvalue to ‘std::basic_ostream<char>&&’
这是我的方法的实现在类中的外观
ostream& operator<<(ostream& out)
{
for (int i = 0; i < this->getHeight(); ++i) {
for (int j = 0; j < this->getWidth(); ++j) {
out << this->(i, j) << "\t";
}
out<< "\n";
}
return out;
}
当我将其实现为这样的功能时
template <typename U>
ostream& operator<<(ostream& out, const Matrix<U>& c)
{
for (int i = 0; i < c.getHeight(); ++i) {
for (int j = 0; j < c.getWidth(); ++j) {
out << c(i, j) << "\t";
}
out << "\n";
}
return out;
}
它的工作原理:(谁能解释我在这里做错了什么
std::ostream& Matrix<U>::operator <<(std::ostream&)具有等效的自由功能签名std::ostream& operator <<(Matrix<U>&, ostream&) ，这不是您想要的（由于多种原因）。
无法将流operator <<或operator >>为UDT的成员函数，因为第一个参数必须始终是流。 您可以使操作员成为friend ，在这种情况下，签名必须为：
template <typename U>
friend std::ostream& operator <<(std::ostream&, Matrix const&);
（同样，请注意，流首先出现，就像您的工作代码中一样。）
您的模板operator <<看起来还不错。 您对此有何异议？
无法绑定'std :: ostream {aka std :: basic_ostream <char> }'左值成'std :: basic_ostream <char> &&”
[英]cannot bind 'std::ostream {aka std::basic_ostream<char>}' lvalue to 'std::basic_ostream<char>&&'
错误：无法绑定 'std::ostream {aka std::basic_ostream<char> }'左值为'std::basic_ostream<char> &&'</char></char>
[英]error: cannot bind 'std::ostream {aka std::basic_ostream<char>}' lvalue to 'std::basic_ostream<char>&&'
std :: vector：无法绑定'std :: ostream {aka std :: basic_ostream <char> ''左右'到'std :: basic_ostream <char> &&”
[英]std::vector : cannot bind 'std::ostream {aka std::basic_ostream<char>}' lvalue to 'std::basic_ostream<char>&&'
错误：无法绑定'std :: basic_ostream <char> '左右'std :: basic_ostream <char> &&”
[英]error: cannot bind ‘std::basic_ostream<char>’ lvalue to ‘std::basic_ostream<char>&&’
重载运算符<<：无法绑定'std :: basic_ostream <char> '左值到'std :: basic_ostream <char> &&'
[英]Overloading operator<<: cannot bind ‘std::basic_ostream<char>’ lvalue to ‘std::basic_ostream<char>&&’
high_resolution_clock错误：无法绑定'std :: ostream {aka std :: basic_ostream <char> }'左值成'std :: basic_ostream <char> &&'
[英]high_resolution_clock error: cannot bind ‘std::ostream {aka std::basic_ostream<char>}’ lvalue to ‘std::basic_ostream<char>&&’
错误：无法绑定'std :: ostream {aka std :: basic_ostream <char> }
[英]Error: cannot bind 'std::ostream {aka std::basic_ostream<char>}
重载operator <<：无法将左值绑定到'std :: basic_ostream <char> &&'
[英]Overloading operator<<: cannot bind lvalue to ‘std::basic_ostream<char>&&’
c++ 无法转换 'std::basic_ostream<char> ::__ostream_type' {aka 'std::basic_ostream<char> '} 赋值给 'int'</char></char>
[英]c++ cannot convert 'std::basic_ostream<char>::__ostream_type' {aka 'std::basic_ostream<char>'} to 'int' in assignment
错误：'operator<<' 不匹配（操作数类型为'std::ostream {aka std::basic_ostream<char> }' 和 'std::ostream {aka std::basic_ostream<char> }')</char></char>
[英]error: no match for ‘operator<<’ (operand types are ‘std::ostream {aka std::basic_ostream<char>}’ and ‘std::ostream {aka std::basic_ostream<char>}’)
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