Question

<预 - >

#include <iostream>

using namespace std;

struct X{
    int _x;
    X(int x=0):_x(x){}
};

int main() {
    X arr[5];
    for (int i = 0;i < 5;i++) {
        arr[i] = i;
    }
    for (int i = 0;i < 5;i++) {
        cout << arr[i] <<",";
    }
    return 0;
}

什么时候必须重载operator <<？

我认为自arr有内注以来我不应该超载<<？

Answer 1

虽然您的proc sort data = have out = sorted; by group replicate ; run; proc transpose data = sorted out = test let; by group replicate ; var observation; id day; run; Obs group replicate _NAME_ _1 _2 1 1 A observation 3 2 2 1 B observation 0 3 3 1 C observation 7 1 4 2 A observation 1 0 5 2 B observation 8 0 6 2 C observation 1 1 7 3 A observation 7 2 8 3 B observation 3 7 9 3 C observation 1 1只是单个X属性的包装，但它与int的类型不同。好消息是你可以通过添加这个函数委托int方法：

int

什么时候必须重载运算符＆lt; <！ - ？

1 个答案: