function&struct.h

编译器很好用

#include"iostream.h"
#include"string.h"

class table{
public:
	char name[11];
	int cat,val,level,addr;
	table * next;
	table(char* Name,int Cat)
	{
		if(Name)
		{
			strcpy(name,Name);
		}
		cat=Cat;
	}
};

class quad{
public:
	char OP[4];
	int arg1,arg2,result;
	int num;
	quad * next;
	quad(char *string,int Arg1,int Arg2,int Result,int Num=1)
	{
		strcpy(OP,string);
		arg1=Arg1;
		arg2=Arg2;
		result=Result;
		num=Num;
	}
};


extern table* t_first;				//符号表的首指针
extern quad* q_first,*q_last;		//四元式的首指针,末指针
int vary_addr=5;					//局部变量的起始地址
extern int const_tab;				//常量表当前大小，在scanner.h中定义

void Gen(char* OP,int result,int arg1,int arg2)	//四元式生成函数
{
	quad* newone;
	if(q_last!=NULL)
	{
		newone=new quad(OP,arg1,arg2,result,q_last->num+1);
		q_last->next=newone;
		newone->next=NULL;
		q_last=q_last->next;
	}else{									//第一个四元式
		newone=new quad(OP,arg1,arg2,result);
		q_first=q_last=newone;
		newone->next=NULL;
	}
}

quad* find(int num)		//跟据四元式的序号，查找相应的四元式指针
{
	quad* temp=q_first;
	while(temp!=NULL)
	{
		if(temp->num==num)
			return temp;
		else
			temp=temp->next;
	}

	return NULL;
}

void backpatch(int q,int t)
{
	int temp;
	quad* current;
	if(q==0)
	{
		return;
	}else{
	
		current=find(q);
		while(current->result!=0)
	{
		temp=current->result;
		current->result=t;
		current=find(temp);
	}

	current->result=t;
	}
}

int merg(int p1,int p2)
{
	quad* current=find(p2);
	
	if(p2==0)
		return p1;
	else{
		if(current->result==0)
	{
		current->result=p1;
		return p1;
	}
	else{
		while((current=find(current->result))->result!=0);//该循环没有语句！

		current->result=p1;
		return p2;
	}
	}
}

void fill(char* id,int k)
{
	table* current=t_first->next;
	table* newone;

	while(current!=NULL)
	{
		if(strcmp(current->name,id)==0)
		{
			cout<<id<<"重定义!"<<endl;
			return;
		}
		
		if(current->next==NULL)
			break;
		else
			current=current->next;
		
	}

	switch(k)
	{
	case 0:
		newone=new table(id,k);
		newone->level=0;			//实验三中level均为0；
		newone->addr=vary_addr++;
		if(current!=NULL)
		{
			current->next=newone;
			newone->next=NULL;
		}else{						//处理首结点
			t_first->next=newone;
			newone->next=NULL;
		}
			break;
	case 1:
		newone=new table(id,k);
		newone->val=const_tab-1;	//常量在常量表中的位置
		if(current!=NULL)
		{
			current->next=newone;
			newone->next=NULL;
		}else{						//处理首结点
			t_first->next=newone;
			newone->next=NULL;
		}
			break;

	case 2:;//实验三不处理;
	}

}

int entry(char *id)
{
	table* current=t_first;
	
	while(current!=NULL)
	{
		if(strcmp(current->name,id)==0)
		{
			if(current->cat==1)
				return 1000+current->val;
			else
				return current->addr;
		}else
			current=current->next;
	}

	return -1;		//查不到刚反回-1
}