ag.cpp

词法分析程序

#include <stdio.h>
#include <math.h>
#include <iostream.h>
#include <string.h>
#include <stdlib.h>
#define M 100
#define N 50
char bsf[N][N],gjz[N][N],jf[N];
int n=0;
int m=0;
int p=0;
void identity(char c[M])
{
	int i=0;
	int j=0;
	int l;
	int t=0;
	char s[M];
    l=strlen(c);
	while(i<l)
	{
		if(c[i]>='a'&&c[i]<='z'||c[i]>='A'&&c[i]<='Z')
		{
            s[j]=c[i];
			i++;
			j++;
			while (c[i]>='a'&&c[i]<'z'||c[i]>='A'&&c[i]<='Z')
			{s[j++]=c[i++];}
			s[j]='\0';
			if (strcmp(s,"main")==0||strcmp(s,"printf")==0||strcmp(s,"int")==0
				||strcmp(s,"for")==0||strcmp(s,"while")==0||strcmp(s,"if")==0||strcmp(s,"char")==0)
			{
				while (t<n&&strcmp(gjz[t],s)!=0)
				{t++;}
				if(t==n) strcpy(gjz[n++],s);
				cout<<"关键字:   "<<s<<endl;
				t=0;
			}
			else 
			{ 
				while (t<m&&strcmp(bsf[t],s)!=0)
				{t++;}
				if(t==m) strcpy(bsf[m++],s);
				cout<<"标示符:    "<<s<<endl;
				t=0;
			}
			j=0;
		}
		
		else if (c[i]>='0'&&c[i]<='9'){
                s[j]=c[i];
				i++;
				j++;
				while (c[i]>='0'&&c[i]<'9'||c[i]=='.')
				{s[j++]=c[i++];}
				s[j]='\0';
				cout<<"数字:   "<<s<<endl;
				j=0;
			}
		else if(c[i]=='<'||c[i]=='>'||c[i]=='+'||c[i]=='-'||c[i]=='*'||c[i]=='/'||c[i]=='='||c[i]=='&')
		{
			printf("运算符：  ");
			printf("%c",c[i]);
		  if(c[i+1]=='=')	  
		  {
			  printf("%c",c[i+1]);	i++;
		  }
		 printf("\n");
		 i++;
	
		  
	 }
	 else if(c[i]==','||c[i]==';'||c[i]=='('||c[i]=='_'||c[i]==')'||c[i]=='{'||c[i]=='}'||c[i]=='['||c[i]==']'||c[i]=='"'||c[i]=='&'||c[i]=='!')
	 {
		 	 printf("界符：  ");
	 		 printf("%c",c[i]);
	 		 printf("\n");
             while (t<p&&jf[t]!=c[i])
			 {t++;}
			 if(t==p) jf[p++]=c[i];
			 i++;
			 t=0;
	 }
	 else if(c[i]=='%'&&c[i+1]=='d'||c[i]=='%'&&c[i+1]=='c'){

		 printf("关键字： ");
		 gjz[n][0]=c[i];
		 printf("%c",c[i++]);
		 gjz[n++][1]=c[i];
	     printf("%c",c[i++]);
		 printf("\n");
	 }
	}
	
}

void main()
{
	FILE *fp;
	char yl[M];
	int i;
	cout<<"\nz******************************词 法 分 析 **************************************"<<endl;
	cout<<"***************************************制作人：杨玲（0215172）******************"<<endl;
	fp=fopen("c.txt","r");
    fscanf(fp,"%s",yl);
 do
 { 
   
   printf("\n********************* # 分 行 词 法 分 析 # ***********************************\n");
   cout<<"源代码：  "<<yl<<"\n"<<endl;
   identity(yl);
   fscanf(fp,"%s",yl);
  }while(! feof(fp));
printf("\n********************* # 词 法 分 析 结 束 # ***********************************\n");
printf("\n**************** # 关键字表，表示符表和界符表如下 ： # ************************\n\n");
 cout<<"此程序中的关键字有："<<endl;
 for(i=0;i<n;i++)
	 cout<<"   "<<gjz[i];
 cout<<"\n此程序中的表示符有："<<endl;
 for(i=0;i<m;i++)
	 cout<<"   "<<bsf[i];
 cout<<"\n此程序中的界符有："<<endl;
 for(i=0;i<p;i++)
	 cout<<"   "<<jf[i];
 cout<<endl;

}