1022 词法分析程序

#include<stdio.h>
#include<string.h>
int n,p,zbm;
char ch,code[1000],str[100];
void scaner();
void main()
{
printf("Please input the source code:\n\n");
p=0;
do{
ch=getchar();
code[p++]=ch;
}while(ch!='#');
printf("\n\nOutput the code:\n\n");
p=0;
do{
scaner();
if(zbm==98)printf("%s",str);
else if(zbm==99)printf("<error,%s>",str);
else printf("<%d,%s>",zbm,str);
}while(zbm!=0);
printf("\n\n");
}
void scaner()
{
do{
ch=code[p++];
}while(ch==' ');
n=0;
if((ch>='A'&&ch<='Z')||(ch>='a'&&ch<='z')||ch=='_')
{
while((ch>='0'&&ch<='9')||(ch>='A'&&ch<='Z')||(ch>='a'&&ch<='z')||ch=='_')
{
str[n++]=ch;
ch=code[p++];
}
str[n++]='\0';
if     (strcmp(str,"begin")==0)zbm=1;
else if(strcmp(str,"if"   )==0)zbm=2;
else if(strcmp(str,"then" )==0)zbm=3;
else if(strcmp(str,"while")==0)zbm=4;
else if(strcmp(str,"do"   )==0)zbm=5;
else if(strcmp(str,"end"  )==0)zbm=6;
else                           zbm=10;
p--;
}
else if(ch>='0'&&ch<='9')
{
zbm=11;
while((ch>='0'&&ch<='9')||(ch>='A'&&ch<='Z')||(ch>='a'&&ch<='z')||ch=='_')
{
if(ch<'0'||ch>'9')zbm=99;
str[n++]=ch;
ch=code[p++];
}
str[n++]='\0';
p--;
}
else
{
switch(ch)
{
case '+':zbm=13;str[n++]=ch; break;
case '-':zbm=14;str[n++]=ch; break;
case '*':zbm=15;str[n++]=ch; break;
case '/':zbm=16;str[n++]=ch; break;
case ':':zbm=17;str[n++]=ch;
if(code[p]=='=')
{    zbm=18;str[n++]=ch;}break;
case '<':zbm=20;str[n++]=ch;
if(code[p]=='=')
{    zbm=21;str[n++]=ch;}break;
if(code[p]=='>')
{    zbm=22;str[n++]=ch;}break;
case'>':zbm=23;str[n++]=ch;
if(code[p]=='=')
{    zbm=24;str[n++]=ch;}break;
case '=':zbm=25;str[n++]=ch; break;
case ';':zbm=26;str[n++]=ch; break;
case '(':zbm=27;str[n++]=ch; break;
case ')':zbm=28;str[n++]=ch; break;
case '#':zbm=0 ;str[n++]=ch; break;
case'\n':zbm=98;str[n++]=ch; break;
case'\t':zbm=98;str[n++]=ch; break;
default :zbm=99;str[n++]=ch;
}
str[n++]='\0';
}
}