state 模式(c++ 实现)

state模式：水蒸汽和冰都是水在不同温度下的状态。将 水，冰，水蒸汽，每种形态看做一种类型。将常温，加热到100度，零下10度，看成是三个动作。

对于水，冰，水蒸汽这三个类来说，对于三个动作都有分别的反应，并且在特定条件下，会变身成其他的类型。例如 水 在 加热到100度 的时候会变身成 水蒸汽。

对于一瓶水来说，我们只需要记录“当前的状态”，然后调用 三个动作的序列，通过 “当前的状态”在不同动作下自身的变化，就能得到最终 这瓶水 的 形态了。

#include <stdio.h>#define SOLD_OUT(0)#define NO_QUARTER(1)#define HAS_QUARTER (0)#define SOLD(3)class GamballMachine{int state;int count;public :GamballMachine(int count){this->count = count;if (count > 0){state = NO_QUARTER;}}void insert_quarter(){if (state == HAS_QUARTER){printf("you can't insert another quarter.\n");}else if (state == NO_QUARTER){state = HAS_QUARTER;printf("you inserted a quarter.\n");}else if (state == SOLD_OUT){printf("you can't insert a quarter, the machine is sold out.\n");}else if (state == SOLD){printf("please wait, we're already giving you a gamball.\n");}}void eject_quarter(){if (state == HAS_QUARTER){printf("quarter returned.\n");state = NO_QUARTER;}else if (state == NO_QUARTER){printf("you haven't inserted a quarter.\n");}else if (state == SOLD_OUT){printf("you can't eject, you haven't inserted a quarter yet.\n");}else if (state == SOLD){printf("sorry. you already turned the crank.\n");}}void turn_crank(){if (state == HAS_QUARTER){printf("you turned.\n");state = SOLD;dispense();}else if (state == NO_QUARTER){printf("you turned, but there is no quarter.\n");}else if (state == SOLD_OUT){printf("you turned, but there is no gamballs.\n");}else if (state == SOLD){printf("the gamball is solding, turned again doesn't take effect.\n");}}void dispense(){if (state == HAS_QUARTER){printf("no gamball dispensed.\n");}else if (state == NO_QUARTER){printf("you need to pay first.\n");}else if (state == SOLD_OUT){printf("no gamball dispensed.\n");}else if (state == SOLD){printf("a gamball comes rolling out of the slot.\n");count = count - 1;if (count == 0){state = SOLD_OUT;}else{state = NO_QUARTER;}}}};int gamball_machine_test(){printf("\n\n===========gamball_machine test=======\n\n");GamballMachine gamball_machine = GamballMachine(5);gamball_machine.insert_quarter();gamball_machine.turn_crank();printf("\n\n");gamball_machine.insert_quarter();gamball_machine.eject_quarter();gamball_machine.turn_crank();return 1;}//use state pattern to rewriteclass State{public :virtual int insert_quarter() = 0;virtual int eject_quarter() = 0;virtual int turn_crank() = 0;virtual int dispense() = 0;};class HasQuarter_State;class NoQuarter_State;class Soldout_State;class Sold_State;class GamballMachine_New{public:State *has_quarter_state;State  *no_quarter_state;State  *soldout_state;State  *sold_state;State  *state;int count;public:GamballMachine_New(int count);public:int set_state(State *state);HasQuarter_State *get_has_quarter_state();NoQuarter_State *get_no_quarter_state();Soldout_State *get_soldout_state();Sold_State *get_sold_state();int insert_quarter();int eject_quarter();int turn_crank();int dispense();};class HasQuarter_State:public State{public:GamballMachine_New *gamball_machine;public:HasQuarter_State(GamballMachine_New *gamball_machine){this->gamball_machine = gamball_machine;}int insert_quarter(){printf("you can't insert another quarter.\n");return 0;}int eject_quarter(){printf("quarter returned.\n");gamball_machine->set_state((State *)gamball_machine->get_no_quarter_state());return 0;}int turn_crank(){printf("you turned.\n");gamball_machine->set_state((State *)gamball_machine->get_sold_state());gamball_machine->dispense();return 0;}int dispense(){printf("no gamball dispensed.\n");return 0;}};class NoQuarter_State:public State{public:GamballMachine_New *gamball_machine;public:NoQuarter_State(GamballMachine_New *gamball_machine){this->gamball_machine = gamball_machine;}int insert_quarter(){gamball_machine->set_state(gamball_machine->get_has_quarter_state());printf("you inserted a quarter.\n");return 0;}int eject_quarter(){printf("you haven't inserted a quarter.\n");return 0;}int turn_crank(){printf("you turned, but there is no quarter.\n");return 0;}int dispense(){printf("you need to pay first.\n");return 0;}};class Soldout_State:public State{GamballMachine_New *gamball_machine;public:Soldout_State(GamballMachine_New *gamball_machine){this->gamball_machine = gamball_machine;}int insert_quarter(){printf("you can't insert a quarter, the machine is sold out.\n");return 0;}int eject_quarter(){printf("you can't eject, you haven't inserted a quarter yet.\n");return 0;}int turn_crank(){printf("you turned, but there is no gamballs.\n");return 0;}int dispense(){printf("no gamball dispensed.\n");return 0;}};class Sold_State:public State{GamballMachine_New *gamball_machine;public:Sold_State(GamballMachine_New *gamball_machine){this->gamball_machine = gamball_machine;}int insert_quarter(){printf("please wait, we're already giving you a gamball.\n");return 0;}int eject_quarter(){printf("sorry. you already turned the crank.\n");return 0;}int turn_crank(){printf("the gamball is solding, turned again doesn't take effect.\n");return 0;}int dispense(){printf("a gamball comes rolling out of the slot.\n");gamball_machine->count = gamball_machine->count - 1;if (gamball_machine->count == 0){gamball_machine->set_state(gamball_machine->get_soldout_state());}else{gamball_machine->set_state(gamball_machine->get_no_quarter_state());}return 0;}};GamballMachine_New::GamballMachine_New(int count){this->state = (new NoQuarter_State(this));this->has_quarter_state = (new HasQuarter_State(this)) ;this->no_quarter_state = (new NoQuarter_State(this));this->soldout_state = (new Soldout_State(this));this->sold_state = (new Sold_State(this));this->count = count;}int GamballMachine_New::set_state(State *state){this->state = state;return 0;}HasQuarter_State* GamballMachine_New::get_has_quarter_state(){return (HasQuarter_State*)has_quarter_state;}NoQuarter_State* GamballMachine_New::get_no_quarter_state(){return (NoQuarter_State*)no_quarter_state;}Soldout_State* GamballMachine_New::get_soldout_state(){return (Soldout_State*)soldout_state;}Sold_State* GamballMachine_New::get_sold_state(){return (Sold_State*)sold_state;}int GamballMachine_New::insert_quarter(){this->state->insert_quarter();return 0;}int GamballMachine_New::eject_quarter(){this->state->eject_quarter();return 0;}int GamballMachine_New::turn_crank(){this->state->turn_crank();return 0;}int GamballMachine_New::dispense(){this->state->dispense();return 0;}int gamball_machine_new_test(){printf("\n\n===========gamball_machine use state pattern test=======\n\n");GamballMachine_New gamball_machine = GamballMachine_New(5);gamball_machine.insert_quarter();gamball_machine.turn_crank();printf("\n\n");gamball_machine.insert_quarter();gamball_machine.eject_quarter();gamball_machine.turn_crank();return 1;}int main(){gamball_machine_test();gamball_machine_new_test();getchar();}