在一个数组中实现两个堆栈pta

Stack CreateStack( int MaxSize ){
	Stack s=(Stack)malloc(sizeof(struct SNode));
	s->Data=(int *)malloc(sizeof(int)*MaxSize);
	s->Top1=-1;
	s->Top2=MaxSize;
	s->MaxSize=MaxSize;
	return s;
}
bool Push( Stack S, ElementType X, int Tag ){
	if(S->Top1+1==S->Top2){
		printf("Stack Full\n");
		return false;
	}
	if(Tag==1){
		S->Top1++;
		S->Data[S->Top1]=X;
		return true;
	}
	else{
		S->Top2--;
		S->Data[S->Top2]=X;
		return true;
	}
}

ElementType Pop( Stack S, int Tag ){
	if(Tag==1){
		if(S->Top1==-1){
			printf("Stack %d Empty\n",Tag);
			return ERROR;
		}
		else {
			int x=S->Data[S->Top1];
			S->Top1--;
			return x;
		}
	}
	else{
		if(S->Top2==S->MaxSize){
			printf("Stack %d Empty\n",Tag);
			return ERROR;
		}
		else{
			int y=S->Data[S->Top2];
			S->Top2++;
			return y;
		}
	}
}