Chained Assignment Runs Right to Left

1#include <iostream>
2#include <string>
3using namespace std;
4 
5class Num {
6    string m_label;
7    int m_value;
8public:
9    Num(const string& label, int value) : m_label(label), m_value(value) {}
10    Num& operator=(const Num& other) {
11        cout << m_label << " = " << other.m_label << " (" << other.m_value << ")" << endl;
12        m_value = other.m_value;
13        return *this;
14    }
15    int value() const { return m_value; }
16};
17 
18int main() {
19    Num a("a", 1), b("b", 2), c("c", 3);
20    a = b = c;
21    cout << a.value() << b.value() << c.value() << endl;
22 
23    Num x("x", 10), y("y", 20);
24    (x = y) = c;
25    cout << x.value() << endl;
26    return 0;
27}