词法分析程序，但是老输不出分析的结果

[local]2[/local]#include <iostream.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
char prog[80], token[8];
char ch;
int syn, p, m, n, sum=0;
char * rwtab[6]={"begin","if","then","while","do","end"};

void scaner()
{

 
         //分别是标示符、数字、符号，对应下面的 if   else if  和 else

    for(n=0;n<8;n++) token[n]=NULL;//初始化
    ch=prog[p++];//读下一个 字符
    while(ch==' ')
    ch=prog[p++];
    if((ch>='a'&&ch<='z')||(ch>='A'&&ch<='Z'))  //ch是字母字符，可能是关键字或者变量名
    {
        m=0;
        while((ch>='0'&&ch<='9')||(ch>='a'&&ch<='z')||(ch>='A'&&ch<='Z'))//ch为字母字符或数字字符
        {
            token[m++]=ch;
            ch=prog[p++];
        }
        token[m++]='\0';
        p--;      //回退一个字符
        syn=10;
        for(n=0;n<6;n++)  //将识别出来的字符和已定义的关键字作比较，
            if(strcmp(token,rwtab[n])==0)
            {
                syn=n+1;
                break;
            }
        }

    else if((ch>='0'&&ch<='9'))  //ch是数字字符
        {
                    sum=0;
                    while((ch>='0'&&ch<='9'))
                    {
                    sum=sum*10+ch-'0';
                    ch=prog[p++];
                    }
           
            p--;//回退一个字符
            syn=11;
            if(sum>32767)
            syn=-1;
        }

    else switch(ch)   //其他字符
  
    {
        case'<':m=0;token[m++]=ch;
            ch=prog[p++];
            if(ch=='>')
            {
                syn=21;
                token[m++]=ch;
            }
            else if(ch=='=')
            {
                syn=22;
                token[m++]=ch;
            }
            else
            {
                syn=23;
                p--;
            }
            break;
        case'>':m=0;token[m++]=ch;
            ch=prog[p++];
            if(ch=='=')
            {
                syn=24;
                token[m++]=ch;
            }
            else
            {
                syn=20;
                p--;
            }
            break;
        case':':m=0;token[m++]=ch;
            ch=prog[p++];
            if(ch=='=')
            {
                syn=18;
                token[m++]=ch;
            }
            else
            {
                syn=17;
                p--;
            }
            break;
        case'*':syn=13;token[0]=ch;break;
        case'/':syn=14;token[0]=ch;break;
        case'+':syn=15;token[0]=ch;break;
        case'-':syn=16;token[0]=ch;break;
        case'=':syn=25;token[0]=ch;break;
        case';':syn=26;token[0]=ch;break;
        case'(':syn=27;token[0]=ch;break;
        case')':syn=28;token[0]=ch;break;
        case'#':syn=0;token[0]=ch;break;
        case'\n':syn=-2;break;
        default: syn=-1;break;
    }
}

void main()
{

   FILE *fin=fopen("in.txt","r");
   FILE *fout=fopen("out.txt","w");
   p=0;
   printf("程序如下：\n");
   while(!feof(fin)&&ch!='#')
    {
        ch=fgetwc(fin);
        prog[p]=ch;
        printf("%c",prog[p]);
        p++;
    }
    printf("\n********************词法分析如下*********************\n");

    p=0;
    do{
        scaner();
        switch(syn)
        {
            case 11: printf("%d","%d",syn,sum); break;
            case -1: printf("error"); break;
            default: printf("%c","%d",syn,token);
   
        }
    }
    while (syn!=0);
    fclose(fin);
    fclose(fout);
}