学习自：操作系统上的程序 - 南京大学jyy

#include<stdio.h>
#include<assert.h>

typedef struct {
    int pc, n;
    char from, to, via;
}Frame;

#define call(...) ({ *( ++ top) = (Frame){.pc = 0, __VA_ARGS__}; })
#define ret() ({ top --; })
#define goto(loc) ({ f->pc = (loc) - 1; })

void hanoi(int n, char from, char to, char via) {
    Frame stk[64], *top = stk - 1;
    call(n, from, to, via);
    for (Frame *f = top; (f = top) >= stk; f->pc ++) {
        switch (f->pc) {
            case 0:
                if (f->n == 1) {
                    printf("move %c -> %c\n", f->from, f->to);
                    ret();
                }
                break;
            case 1:
                call(f->n - 1, f->from, f->via, f->to);
                break;
            case 2:
                printf("move %c -> %c\n", f->from, f->to);
                break;
            case 3:
                call(f->n - 1, f->via, f->to, f->from);
                break;
            case 4:
                ret();
                break;
            default:
                assert(0);
        }
    }
}

int main()
{
    hanoi(4, 'A', 'B', 'C');
    return 0;
}