状态模式--示例代码

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
typedef struct{
  int index;
}Owner;
 typedef enum{
    START,PLAY,STOP    
 }State;
State startState(Owner *owner){
  owner->index++;
  printf("..");
  if(owner->index%5==0){
    printf(">>");
    return PLAY;
  }
  return START;
}
State playState(Owner *owner){
  owner->index++;
  switch(owner->index%5){
    case 0: case 3: case 2:printf("~!~");break;
    case 1: printf("~@~");break;
    case 4: printf(">>");return STOP;
  }
  return PLAY;
}
State stopState(Owner *owner){
  owner->index++;
  printf("**");
  if(owner->index%5==1){
    printf(">>");
   return START; 
  } 
  return STOP;
}
typedef State (*HandleState)(Owner *);
HandleState handleState[]={startState,playState,stopState};
int main(){
  Owner owner={0};
  State currentState=STOP;
  for(int i=0;i<100;i++){
    currentState=handleState[currentState](&owner);
  }
  return 0;
}

typedef struct {
    void (*handle)(void);
} State;

void handleStateA() { printf("State A\n"); }
void handleStateB() { printf("State B\n"); }
State stateA = { .handle = handleStateA };
State stateB = { .handle = handleStateB };

typedef struct {
    State* currentState;
} Context;

// 使用
Context ctx = { .currentState = &stateA };
ctx.currentState->handle(); // 输出 "State A"