pascal.cpp

计算机专业编译原理课程设计编程 只有代码

#include<iostream.h> 
#include<stdio.h> 
#include<stdlib.h>  //输出文件的头文件
#include<string.h> 
#include<ctype.h> //漏掉注释符的头文件 
const long stakmax=10000; //定义栈的最大长度
int hang; //标志
char Ischeck[]={' ','\n','+','-','*','(',')','{','}', 
';','=','\"','%',',','&','[',']','!','#',':','\\','<','>','\'','/'}; //字符数组,用来存放标号界符共26个
const char keyword[][20]={"int","void","if", 
"char","bool","break","case", 
"catch","const","for","else", 
"continue","class","while", 
"do","goto","float","double", 
"long","switch","friend","static", 
"public","private","protected", 
"return","struct","signed","array","program"}; 
//2维字符数组用来存放关键字共30个
struct stack //定义一个栈结构
{
	char stak[stakmax]; //栈的大小为stakmaxsize
	int top;
};
bool isCheck(const char& ch) //判别字符是否为标点符号
{
	for(int i=0;i<29;i++)
		if(ch==Ischeck[i])
			return true;
		return false;
}
void initstak(stack& s) //初使化栈
{
	s.top=-1;
}
void clearstak(stack& s) //清空栈
{
	s.top=-1;
}
void push(stack& s,const char& item) //字符入栈
{
	if(s.top==stakmax-1) //如果栈满则输出'溢出'
	{
		cerr<<"溢出了"<<endl;
		exit(1);
	}
	else 
	s.top++;              //栈不满,栈头指针top增1,字符入栈
	s.stak[s.top]=item;
}
bool isKeyword(stack& s) //判别是否为关键字
{
	for(int i=0;i<30;i++)
		if(!strcmp(s.stak,keyword[i])) //strcmp字符比较函数
			return true;
		return false;
}
void printout(stack& s) //判别字符是'关键字'还是'标识符'
{
	if(isKeyword(s))
		cout<<"("<< 1 <<","<<s.stak<<")"<< endl;//是关键字则用1表示
	else 
	{
		cout<<"("<< 2 <<","<<s.stak<<")"<< endl;//是标识符则用2表示
	}
}
void digitpush(stack& s,const char& item) //数字进栈
{
	if(s.top==stakmax-1) //栈满
	{
		cerr<<"溢出了"<<endl;
		exit(1);
	}
	s.top++;                  //栈不满,栈头指针top增1,字符入栈
	s.stak[s.top]=item;	
}
void Getchar(FILE *fp,char& ch) //从指定文件取字符
{
	ch=fgetc(fp); //fgetc()从指定的文件读入一个字符,该文件必须是以读或读写的方式打开的
	if(ch=='\n') //如果ch='\n',则ren增1,ren为一个标号,当出错时用来指出出错位置所在行
		hang++;
	if(feof(fp))      //feof()若到文件尾,函数值为"真"
	{
		fclose(fp);       //fclose() 关闭文件
		getchar();   //getchar()函数返回stdin中的下一个字符.如果达到文件尾,getchar()返回EOF.如果遇到错误,也返回EOF.
		exit(1);
	}
}
void digitprint(stack& s) //输出数字函数
{
	cout<<"数字:"<<s.stak<<endl;
}
void check(char *fname)
{
	FILE *fp;
	bool watch=false,checked=true; //设立watch,checked,ren的初值
	hang=1;
	if((fp=fopen(fname,"r"))==NULL) //判断能否打开文件,文件以读的方式打开
	{
		cerr<<"文件"<<"\'"<<fname<<"\'"<<"找不到"<<endl;
		getchar(); 
		exit(1);
	}
	stack a; //声明变量,函数部分
	initstak(a); 
	char ch; 
	Getchar(fp,ch);
	while(!feof(fp))
	{
		if(ch==' '||ch=='\n')
		{
			Getchar(fp,ch); 
			checked=true; 
			continue;
		}
		else if(checked && isalpha(ch)) //判断是否为字母，是字母返回1，否则返回0，checked查看上次有没有输入错误
		{
			while(isalnum(ch)) //判断是否是字母和数字的组成，是返回1，否则返回0
			{
				 if(isCheck(ch))
					 break;
				 push(a,ch); //字符入栈
				 Getchar(fp,ch); //从栈中取字符
			}
			if(isCheck(ch))
			{
				push(a,'\0'); //'\0'代表空操作
				printout(a); //输出栈中字符
				clearstak(a); //清空栈
			}
			else
			{
				cout<<"错误位置"<<hang<<endl; //出错处理
				checked=false;
				clearstak(a);
				continue;
			}
		}
		else if(isdigit(ch) && checked)//判断是否为数字。是返回1，否则返回0，checked表示检查
			//上次输入有没有错误
		{
			while(isdigit(ch)||ch=='.')
			{
				if(ch=='.')
					watch=true;
				if(isCheck(ch))
					break;
				digitpush(a,ch); //数字入栈
				Getchar(fp,ch); //从栈中取数字
			}
			if(isCheck(ch))
			{
				if(watch) //如果watch 为真,则输出浮点型数
				{
					cout<<"float";
					watch=false; //重新将watch 置为false
					digitpush(a,'\0');
					digitprint(a);
					clearstak(a);
				}
				else
				{
					cout<<"int";//如果watch 为假则输出整数
					digitpush(a,'\0');
					digitprint(a);
					clearstak(a);
				}
			}
			else //出错处理
			{
				cout<<"有错误"<<hang<<endl;
				checked=false; //重新将watch 置为false
				clearstak(a);
				continue;
			}
		}
		else if(checked) //关系运算符的识别用3表示,如果checked 为真则执行以下语句
		{
			switch(ch)
			{
				case'!': Getchar(fp,ch);//函数Getchar(fp,ch)的功能是从文件fp中取字符
					if(ch=='=')
					{
						cout<<"("<< 3 <<","<<"!="<<")"<< endl;
						Getchar(fp,ch);
						checked=true;
						break;
					}
					else
					{
						cout<<"("<< 3 <<","<<"!"<<")"<< endl;
						checked=true;
						break;
					}
				case'=': Getchar(fp,ch); 
					if(ch=='=')
					{
						cout<<"("<< 3 <<","<<"=="<<")"<< endl;
						Getchar(fp,ch);
						checked=true;
						break;
					}
					else
					{
						cout<<"("<< 3 <<","<<"="<<")"<< endl;
						checked=true;
						break;
					}
				case'+': Getchar(fp,ch);
					if(ch=='=')
					{
						cout<<"("<< 3 <<","<<"+="<<")"<< endl;
						Getchar(fp,ch);
						checked=true;break;
					}
					else if(ch=='+')
					{
						cout<<"("<< 3 <<","<<"++"<<")"<< endl;
						Getchar(fp,ch);checked=true;
						break;
					}
					else
					{
						cout<<"("<< 3 <<","<<"+"<<")"<< endl;
						checked=true;break;
					}
				case'*':Getchar(fp,ch);
					if(ch=='=')
					{
						cout<<"("<< 3 <<","<<"*="<<")"<< endl;
						Getchar(fp,ch);checked=true;
						break;
					}
					else
					{
						cout<<"("<< 3 <<","<<"*"<<")"<< endl;
						checked=true;break;
					}
				case'/': cout<<"("<< 3 <<","<<"/"<<")"<< endl;
					Getchar(fp,ch);checked=true;
					break;
				case'-': Getchar(fp,ch);
					if(ch=='=')
					{
						cout<<"("<< 3 <<","<<"-="<<")"<< endl;
						Getchar(fp,ch);checked=true;
						break;
					}
					else if(ch=='-')
					{
						cout<<"("<< 3 <<","<<"--"<<")"<< endl;
						Getchar(fp,ch);
						checked=true;
						break;
					}
					else
					{
						cout<<"("<< 3 <<","<<"-"<<")"<< endl;
						checked=true;
						break;
					}
				case'>':
					Getchar(fp,ch);
					if(ch=='=') 
					{
						cout<<"("<< 3 <<","<<">="<<")"<< endl;
						Getchar(fp,ch);
						checked=true;
						break;
					} 
					else 
					{
						cout<<"("<< 3 <<","<<">"<<")"<< endl;
						checked=true;
						break;
					}
				case'<':
					Getchar(fp,ch);
					if(ch=='=') 
					{
						cout<<"("<< 3 <<","<<"<="<<")"<< endl;
						Getchar(fp,ch);
						checked=true;
						break;
					} 
					else 
					{
						cout<<"("<< 3 <<","<<"<"<<")"<< endl;
						checked=true;
						break;
					}
				case')':
					cout<<"("<<4<<","<<")"<<")"<<endl;
					Getchar(fp,ch);
					checked=true;
					break;
				case'[':
					cout<<"("<<4<<","<<"["<<")"<<endl;
					Getchar(fp,ch);
					checked=true;
					break;
				case'(':
					cout<<"("<<4<<","<<"("<<")"<<endl;//界符用4表示
					Getchar(fp,ch);
					checked=true;
					break;
				case'}':
					cout<<"("<<4<<","<<"}"<<")"<<endl;
					Getchar(fp,ch);
					checked=true;
					break; 
				case']':
					cout<<"("<<4<<","<<"]"<<")"<<endl;
					Getchar(fp,ch);
					checked=true;
					break; 
				case';':
					cout<<"("<<4<<","<<";"<<")"<<endl;
					Getchar(fp,ch);
					checked=true;
					break;
				case'\'':
					cout<<"("<<4<<","<<"\\"<<")"<<endl;
					Getchar(fp,ch);
					checked=true;
					break; 
				case',':
					cout<<"("<<4<<","<<","<<")"<<endl;
					Getchar(fp,ch);
					checked=true;
					break; 
				case'%':
					cout<<"("<<4<<","<<"%"<<")"<<endl;
					Getchar(fp,ch);
					checked=true;
					break; 
				case'#':
					cout<<"("<<4<<","<<"("<<"#"<<endl;
					Getchar(fp,ch);
					checked=true;
					break; 
				case'&':
					cout<<"("<<4<<","<<"("<<"&"<<endl;
					Getchar(fp,ch);
					checked=true;
					break; 
				case':':
					cout<<"("<<4<<","<<"("<<":"<<endl;
					Getchar(fp,ch);
					checked=true;
					break; 
				case'\"':
					cout<<"("<<4<<","<<"\""<<")"<<endl;
					Getchar(fp,ch);
					checked=true;
					break;
				case'\n':break;
				case'\\': 
					Getchar(fp,ch);
					if(ch=='n')
					{
						cout<<"("<<4<<","<<"\\n"<<")"<<endl;
						Getchar(fp,ch);
						checked=true;
						break;
					}
					else
					{
						cout<<"("<<4<<","<<"\\"<<")"<<endl;
						checked=true;
						break;
					} 
				case' ': break; 
				default:
					cout<<"错误在第"<<hang<<"行"<<endl;
					checked=false;
					Getchar(fp,ch);
			}
		}
		
	}
}
void main()
{
	char filenames[100];
	cout<<"                                                            \n ";
	cout<<"                  Pascal词法分析器"<<endl;
	cout<<"                                    "<<endl;
	cout<<"                                    "<<endl;
	cout<<"请输入你所要分析的程序所在的路径(文件名用英文或数字命名):"<<endl; 
	cin>>filenames; 
	cout<<"\n              词法分析结果              \n"<<endl;
	cout<<"单词符号"<<"     "<<"单词符号的属性值"<<endl;
	
	check(filenames);
}