没有用于'ostream_iterator< int>'的初始化的匹配构造函数 [英] No matching constructor for initalization of 'ostream_iterator<int>'
问题描述
代码,为什么错误,osteam_iterator是一个模板类,为什么没有匹配构造函数用于'ostream_iterator'的初始化,请给予帮助,谢谢。
define ostream_iterator
template>
class _LIBCPP_VISIBLE ostream_iterator
for the code, why error, osteam_iterator is a template class ,why no matching constructor for initalization of 'ostream_iterator', please give a help , thank you. define ostream_iterator template > class _LIBCPP_VISIBLE ostream_iterator
int main(int argc, const char * argv[])
{
vector<int> sentence1;
sentence1.reserve(5);// 设置每次分配内存的大小
sentence1.push_back(1);
sentence1.push_back(2);
sentence1.push_back(3);
sentence1.push_back(4);
sentence1.push_back(5);
int c = 5;
copy(sentence1.begin(), sentence1.end(), ostream_iterator<int>(cout, 1));
cout << endl;
推荐答案
ostream_iterator类定义如下:
The ostream_iterator class definition looks like:
template< class T,
class CharT = char,
class Traits = std::char_traits<charT>>
class ostream_iterator /*...*/
而相应的构造函数声明为:
whereas the respective constructor is declared as:
ostream_iterator(ostream_type& buffer, const CharT* delim)
由于 ostream_iterator
的第二个模板参数必须是字符类型,因此不能简单地用int替换它。
Since the second template argument of an ostream_iterator
is required to be of character type you cannot simply replace it with int.
如果省略第二个模板参数,可以插入类型为 char const *
的字符串文字:
If you ommit the second template parameter you can plug in a string literal of type char const *
:
std::copy(sentence1.begin(), sentence1.end(), std::ostream_iterator<int>(cout, ","));
如果您可以使用C ++ 11,那么
If C++11 is available to you then
int c = 5;
for ( auto v : sentence1 ) std::cout << v << c;
是做你应得的另一种方式,也可能是合适的。
优点是,运算符<<
比指向char类型的指针类型的参数更灵活。
is another way of doing what you deserve and it might be suitable, too.
The advantage is, that operator<<
is more flexible than an argument of type "pointer to char type".
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