hello.cpp

很好的c语言词法分析程序

// hello.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
//C语言词法分析器 
#include<iostream> 
#include<stdio.h> 
#include<string> 
using namespace std; 
FILE *f; //定义一个文件变量 
static int line = 1; //表示光标所在的行数 
struct ID
{ 
	char *name;
	int count;
}id[100];//用于存放ID号码 
static int I = 0; //用于记录ID存放的数量 
int Number[100]; //用于存放数字 
static int P = 0; //用于记录存放数字的个数 
int error[100] = {0}; //用于记录错误所在的行数 
static int K = 0; //记录错误次数 
void Error(); //记录错误 
void loginID(char *); //注册ID号 
void loginNumber(int &); //记录数字 
void noteLine(char &); //记录光标所在的行数 
void print(); //输出分析结果 
int same(char *chr); //判断单词是否已经存在 
void Error() 
{ error[K++] = line; } 

void loginID(char *chr) //注册ID号 
{ 
	int k = 0; 
	int h = 0; 
	for(int i = 0; i < I; i++) 
	{ 
		if(!strcmp(chr,id[i].name)) //如果单词已经存在 
		{ 
			id[i].count++; 
			k = 1; 
		} 
	} 
	if(k == 0) //该单词不存在 
	{ 
		h = I + 1; 
		//I = h; 
		id[h].count++; 
		id[h].name = chr; 
		//strcpy(id[h].name ,chr); 
	} 
	
} 


void loginNumber(int &nu) 
{ Number[P++] = nu; } 

void noteLine(char &ch) 
{ 
	if ( ch == ' ' ) 
		++line; 
} 

void print()//输出部分 
{ 
	//cout << "关键字以及变量:" << endl; 
	//for(int i = 0; i < 100; i++) 
	//cout << i <<" " << id.name << " " << id.count << endl; 
	cout << "数字：" << endl; 
	for(int i = 1; i <= P; i++) 
		cout << i << ": " << Number[i-1] << endl; 
	if(error[0] != 0) 
	{ 
		cout << "出现的错误！" << endl; 
		for(int i = 1; i <= K; i++) 
			cout << "第" << i << "个错误： " << "第" << error[i-1] << "行" << endl; 
	} 
	else cout << "没有错误！" << endl; 
} 

//文件处理部分 
void noblank( char &ch) //跳过空格，回车 
{ 
	noteLine(ch); 
	while(ch == ' ' || ch == ' ') 
		ch = fgetc(f); 
} 

void identifier(char name[],char &ch)//字母变量 
{ 
	
	int i; 
	for(i = 0; i < 20; i++) 
		name[i] =' '; 
	i = 0; 
	while (('0'<= ch && ch <= '9')||('a'<= ch&&ch <= 'z')||('A'<= ch&&ch <='Z')) 
	{ 
		name[i] = ch; 
		i++; 
		ch = fgetc(f); 
	} 
	loginID(name); 
	//for(int j = 0; j < i; j++) 
	//{cout << name[j];} 
	// cout << ' '; 
	
} 

int number(char &ch)//数字 
{ 
	int num=0; 
	while('0'<= ch && ch <= '9') 
	{ 
		num = num* 10 + (ch-'0'); 
		ch = fgetc(f); 
	} 
	if( ('a'<= ch&&ch <= 'z')||('A'<= ch&&ch <='Z')) 
	{ 
		Error(); 
	} 
	else if( ch == '.') 
	{;} 
	loginNumber(num); //记录数字 
	return num; 
} 

void test(char &ch)//符号 
{ 
	char str[2]={'0'}; 
	if(ch == '*') 
	{ str[0] = ch; ch = fgetc(f);} 
	if(ch == '.') 
	{ str[0] = ch; ch = fgetc(f);} 
	if(ch == ',') 
	{ str[0] = ch; ch = fgetc(f);} 
	if(ch == '"') 
	{ str[0] = ch; ch = fgetc(f);} 
	if(ch == '/') 
	{ str[0] = ch; ch = fgetc(f);} 
	if(ch == '%') 
	{ str[0] = ch; ch = fgetc(f);} 
	if(ch == '^') 
	{ str[0] = ch; ch = fgetc(f);} 
	if(ch == '-') 
	{ str[0] = ch; ch = fgetc(f);} 
	if(ch == '{') 
	{ str[0] = ch; ch = fgetc(f);} 
	if(ch == '}') 
	{ str[0] = ch; ch = fgetc(f);} 
	if(ch == '[') 
	{ str[0] = ch; ch = fgetc(f);} 
	if(ch == ']') 
	{ str[0] = ch; ch = fgetc(f);} 
	if(ch == ';') 
	{str[0] = ch; ch = fgetc(f);} 
	if(ch == ':') 
	{ str[0] = ch; ch = fgetc(f);} 
	if(ch == '?') 
	{ str[0] = ch; ch = fgetc(f);} 
	if(ch == '(') 
	{ str[0] = ch; ch = fgetc(f);} 
	if(ch == ')') 
	{str[0] = ch; ch = fgetc(f);} 
	if(ch =='+') 
	{ 
		
		str[0] = ch; 
		if((ch = fgetc(f)) == '+' ) 
		{ 
			str[1] = ch; 
			ch = fgetc(f); 
			//cout << str[0] << str[1] << endl; 
		} 
		
		//cout << str[0]<< endl; 
	} 
	if(ch == '-') 
	{ 
		
		str[0] = ch; 
		if((ch = fgetc(f)) == '-' ) 
		{ 
			str[1] = ch; 
			ch = fgetc(f); 
			//cout << str[0] << str[1] << endl; 
		} 
		
		//cout << str[0]<< endl; 
	} 
	if(ch == '&') 
	{ 
		
		str[0] = ch; 
		if((ch = fgetc(f)) == '&' ) 
		{ 
			str[1] = ch; 
			ch = fgetc(f); 
			//cout << str[0] << str[1] << endl; 
		} 
		
		//cout << str[0]<< endl; 
	} 
	if(ch == '|') 
	{ 
		
		str[0] = ch; 
		if((ch = fgetc(f)) == '|' ) 
		{ 
			str[1] = ch; 
			ch = fgetc(f); 
			//cout << str[0] << str[1] << endl; 
		} 
		
		//cout << str[0]<< endl; 
	} 
	if(ch == '!') 
	{ 
		
		str[0] = ch; 
		if((ch = fgetc(f)) == '=' ) 
		{ 
			str[1] = ch; 
			ch = fgetc(f); 
			//cout << str[0] << str[1] << endl; 
		} 
		
		//cout << str[0]<< endl; 
	} 
	if(ch == '=') 
	{ 
		
		str[0] = ch; 
		if((ch = fgetc(f)) == '=' ) 
		{ 
			str[1] = ch; 
			ch = fgetc(f); 
			//cout << str[0] << str[1] << endl; 
		} 
		
	} 
	if(ch == '>') 
	{ 
		
		str[0] = ch; 
		if((ch = fgetc(f)) == '=' ) 
		{ 
			str[1] = ch; 
			ch = fgetc(f); 
			//cout << str[0] << str[1] << endl; 
		} 
		else 
			if(ch == '>' ) 
			{ 
				str[1] = ch; 
				ch = fgetc(f); 
				//cout << str[0] << str[1] << endl; 
			} 
			
	} 
	if(ch == '<') 
	{ 
		str[0] = ch; 
		if((ch = fgetc(f)) == '=' ) 
		{ 
			str[1] = ch; 
			ch = fgetc(f); 
		} 
		else 
			if(ch == '<' ) 
			{ 
				str[1] = ch; 
				ch = fgetc(f); 
			} 
			
	} 
	
} 

int main() 
{ 
	char ch; 
	char name[30]; 
	for(int i = 0; i < 30; i++) 
		name[i] = '0'; 
	f = fopen("c.txt","r"); //打开指定输入文件 
	if (f == NULL) 
		cout<<"文件不存在！"<<endl; 
	ch = fgetc(f); 
	while(!feof(f)) 
	{ 
		noblank( ch ); //跳过回车，空格 
		if( ( ch >= 'a' && ch <= 'z' )||( ch >= 'A' && ch <= 'Z' )) 
		{ identifier(name,ch); } //处理字母 
		else if( ch >= '0'&& ch <= '9') 
		{ number(ch); } //处理数字 
		else 
		{ test(ch); } //处理符号 
	} 
	print(); //打印词法分析结果 
	fclose(f); //关闭文件 
	system("pause"); 
	return 0; 
}