如何使用std :: copy来打印用户定义的类型

问题描述

下面的代码非常适合打印std::string

Below is the code that works perfectly for print the values of type std::string

std::vector<std::string> v;
v.push_back("this");
v.push_back("is");
v.push_back("a");
v.push_back("test");
std::copy(v.begin(),v.end(),std::ostream_iterator<std::string>(std::cout,","));

但是当我尝试打印用户定义的类型(结构)时，代码无法编译:

But when I am trying to print a user defined type (a structure), code is not compiling:

struct Rec
{
    int name;
    int number;
    int result;
};
int main()
{
    Rec rec1 = {1,1,1};
    Rec rec2 = {2,1,1};
    Rec rec3 = {3,1,1};
    Rec rec4 = {4,1,1};
    Rec rec5 = {4,1,1};

    std::vector<Rec> v;
    record.push_back(rec1);
    record.push_back(rec2);
    record.push_back(rec3);
    record.push_back(rec4);
    record.push_back(rec5);

    std::copy(v.begin(),v.end(),std::ostream_iterator<Rec>(std::cout,","));

    return 1;
}

我在这里想念什么?

推荐答案

来自 std :: ostream_iterator

(经评论确认)

对于自定义记录，您不会超载operator <<.使用以下代码使运算符重载.

You are not overloading operator << for the custom record. Use the following code to overload the operator.

ostream& operator<<(ostream& os, const Rec& r)
{
    os << r.name << '-' << r.number << '-' << r.result;
    return os;
}

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