analyze.c

我的词法分析程序

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define PEND ":END"
//字符串":END"表示输入的结束
#define MAX_LENGTH 70
//每行的最大长度
/***********************************************************************************/
struct InPut
{char data[MAX_LENGTH];
struct InPut *next;
};
/***********************************************************************************/
struct InPut *text_input()
{char forinput[MAX_LENGTH];
struct InPut *p,*head,*r;
head=(struct InPut *)malloc(sizeof(struct InPut));
r=head;
gets(forinput);
while(strcmp(PEND,forinput)!=0)//如果该输入的字符串不为结束字符串的话,生成节点
    {p=(struct InPut *)malloc(sizeof(struct InPut));
     strcpy(p->data,forinput);
     r->next=p;
     r=p;
     gets(forinput);
    }
r->next=NULL;
return head;
}
/***********************************************************************************/
int wch(char a)//
{if((a>='A'&&a<='Z')||(a>='a'&&a<='z')||(a>='0'&&a<='9')||(a=='_'))return 1;
 else return 0;
}
/***********************************************************************************/
print()
{printf("----------------------------------------------\n");
 printf("单词类型表\n");
 printf("(1,基本字)\n(2,标识符)\n(3,常数)\n(4,运算符)\n(5,界符)\n");
 printf("----------------------------------------------\n");
 printf("关键字:\n");
 printf("(1,main)\n(2,if)\n(3,int)\n(4,while)\n(5,else)\n");
 printf("----------------------------------------------\n");
 printf("运算符:\n");
 printf("(1,'(')\n(2,')')\n(3,'>')\n(4,'<')\n(5,'+')\n(6,'-')\n(7,'*')\n(8,'/')\n");
 printf("----------------------------------------------\n");
 printf("界符:\n");
 printf("(1,',')\n(2,';')\n");
 printf("----------------------------------------------\n");
}
/***********************************************************************************/
int wkey(char a[20])//判断是否关键字
{if(strlen(a)==0)return -1;
 if(strcmp("main",a)==0)return 1;
 if(strcmp("if",a)==0)return 2;
 if(strcmp("int",a)==0)return 3;
 if(strcmp("while",a)==0)return 4;
 if(strcmp("else",a)==0)return 5;
 else return 0; 
}
/***********************************************************************************/
int wconst(char a[20])//判断是否是常数
{int i=0,N;
 N=strlen(a);
 while(i<N)
    {if(a[i]>='0'&&a[i]<='9')i++;
     else break;
    }
 if(i==N) return 1;
 else return 0;
}
/***********************************************************************************/
main()
{
struct InPut *p,*q,*forprint,*head,*r,*fortest;
int N,i,j,count,count1=0;
char temp[20];
printf("请输入源程序：\n");
p=text_input();
p=p->next;
head=(struct InPut *)malloc(sizeof(struct InPut));//建立一个变量表
r=head;
r->next=NULL;//变量表的初始为空
while(p!=NULL)
   {i=0;j=0;
	N=strlen(p->data);
    while(i<=N+1)
	{   if(wch(p->data[i])==1)temp[j++]=p->data[i++];
	    else if(p->data[i]=='\0') {temp[j]='\0',i++;}
	    else
		{  temp[j]='\0';
			if(wkey(temp)==0&&wconst(temp)==0)//输入字符为变量
                 {count=0;
			  fortest=head->next;
              if(r==head)
                {
                 q=(struct InPut *)malloc(sizeof(struct InPut));
                 strcpy(q->data,temp);
                 q->next=r->next;
                 r->next=q;
                 r=r->next;
				 count++;
                }
              else
                 {while(fortest!=NULL)
                    {if(strcmp(fortest->data,temp)==0)
                       {count++;
                        break;
                       }
                     else 
                       {fortest=fortest->next;
                       count++;
                       }
                    }
                  if(fortest==NULL)//将该变量加入到变量表中
                    {q=(struct InPut *)malloc(sizeof(struct InPut));
                     strcpy(q->data,temp);
                     q->next=r->next;
                     r->next=q;
                     r=r->next;
                     count++;
                    }
                 }
             printf("(2,%d,%s)\n",count,temp);
	         j=0;
             }
	    else if(wkey(temp)!=0&&wkey(temp)!=-1)//关键字
	             {printf("(1,%d,%s)\n",wkey(temp),temp);
		      j=0;
		     }
	    else if(wconst(temp)==1&&strlen(temp)!=0)//常数
	             {printf("(3,%s)\n",temp);
		      j=0;
		     }
	   switch(p->data[i])//打印界符和运算符
               {case '\0':break;
				case '(':printf("(4,1,'(')\n");break;
                case ')':printf("(4,2,')')\n");break;
                case '>':printf("(4,3,'>')\n");break;
                case '<':printf("(4,4,'<')\n");break;
                case '=':printf("(4,5,'=')\n");break;
			    case '{':printf("(4,6,'{')\n");break;
			    case '}':printf("(4,7,'}')\n");break;
                case ',':printf("(5,1,',')\n");break;
                case ':':printf("(5,2,';')\n");break;
               }
		i++;
          }
       }
       p=p->next;
       
   }
 printf("附表:\n");
 print();
 forprint=head->next;
 if(forprint==NULL)printf("该程序中没有变量\n");
 else
   {printf("变量:\n");  
    while(forprint!=NULL)
	{printf("(%d,%s)\n",++count1,forprint->data);
	 forprint=forprint->next;
	}
   }
}