C++ 运算符重载

#include 
#include 
#include 
using namespace std;
 
typedef struct data
{
    int a;
    char str[100];
 
} data;
// 单木运算符
data operator++(data &d, int) // 后置++
{
    data temp = d;
    d.a++;
    cout << "后置++" << endl;
    return temp;
}
 
data operator++(data &d) // 前置++
{
    d.a++;
    cout << "前置++" << endl;
    return d;
}
 
// 双目运算符
data operator+(data &d1, data &d2) // 重载+
{
    strcat(d1.str, d2.str);
    return d1;
}
 
bool operator>(data &d1, data &d2) // 重载>
{
    return d1.a > d2.a;
}
 
// 位运算符重载
ostream &operator<<(ostream &out, data &d) // 重载<< cout只能传引用
{
    out << d.a << endl;
    out << d.str;
    return out;
}
 
// 重载>>
istream &operator>>(istream &in, data &d) // 重载>>
{
 
    in >> d.a;
    in >> d.str;
    return in;
}
 
int main(int argc, char const *argv[])
{
 
    data d;
    data d1;
    d1.a = 1;
    d.a = 10;
    strcpy(d1.str, " word");
    strcpy(d.str, "hello");
 
    cout << "重载后置++" << endl;
    cout << d++.a << endl;
    cout << d.a << endl;
 
    cout << "重载前置++" << endl;
    cout << ++d.a << endl;
    cout << d.a << endl;
 
    cout << "重载+" << endl;
    cout << (d + d1).str << endl;
 
    cout << "重载>" << endl;
    cout << (d > d1) << endl;
    cout << (d1 > d) << endl;
 
    cout << "重载<<" << endl;
    cout << d << endl;
 
    cout << "重载>>" << endl;
    cin >> d;
    cout << d << endl;
    return 0;
}

为了方便我们类操作，时常需要用到运算符重载。

注意:

        对类的等号（=）操作重载需要禁止隐式转换，且要在类内对等号重载；