#include <stdio.h>

int &demo() // ==> int* const
{
    int d = 0;

    printf("demo: d = %d\n", d);

    return d; // ==> return &d;
}

int &func()
{
    static int s = 0;

    printf("func: s = %d\n", s);

    return s; // ==> return &s
}

int main(int argc, char **argv)
{
    int &rd = demo();
    int &rs = func();

    printf("\n");
    printf("main: rd = %d\n", rd);
    printf("main: rs = %d\n", rs);
    printf("\n");

    rd = 10;  // Error: rd 指向的内存已释放
    rs = 11;

    demo();
    func();

    printf("\n");
    printf("main: rd = %d\n", rd);
    printf("main: rs = %d\n", rs);
    printf("\n");

    return 0;
}