关于keyword[N]的问题

http://hi.baidu.com/zycx2007/blog/item/fe97f1d9e5c7c52f11df9b3b.html
实验程序代码

//词法分析程序

//TESTscan.cpp

#include

#include

#include

#define keywordSum 9

char *keyword[keywordSum]={"if","else","for","while","do","int","read","write","real"};

char singleword[50]="+-*(){};,:&";

char doubleword[10]="><=!||";

extern char Scanin[300], Scanout[300];

extern FILE *fin,*fout;

int TESTscan()

{

char ch,token[40];

int es=0,j,n;

printf("请输入源程序文件名（包括路径）：");

scanf("%s",Scanin);

printf("请输入词法分析输出文件名（包括路径）：");

scanf("%s",Scanout);

if((fin=fopen(Scanin,"r"))==NULL)

{

printf("\n打开词法分析输入文件出错!\n");

return(1);//输入文件出错返回错误代码1

}

if((fout=fopen(Scanout,"w"))==NULL)

{

printf("\n创建词法分析输出文件出错!\n");

return(2);

}

ch=getc(fin);

while(ch!=EOF)

{

while(ch==' '||ch=='\n'||ch=='\t')

ch=getc(fin);

if(isalpha(ch))

{

token[0]=ch;

j=1;

ch=getc(fin);

while(isalnum(ch))

{

token[j++]=ch;

ch=getc(fin);

}

token[j]='\0';

n=0;

while((n
n++;

if(n>=keywordSum)

fprintf(fout,"%s\t%s\n","ID",token);

else

fprintf(fout,"%s\t%s\n",token,token);

}

else if(isdigit(ch))

{

token[0]=ch;

j=1;

ch=getc(fin);

while(isdigit(ch))

{

token[j++]=ch;

ch=getc(fin);

}

token[j]='\0';

fprintf(fout,"%s\t%s\n","NUM",token);

}

else if(strchr(singleword,ch)>0)

{

token[0]=ch;

token[1]='\0';

ch=getc(fin);

fprintf(fout,"%s\t%s\n",token,token);

}

else if(strchr(doubleword,ch)>0)

{

token[0]=ch;

ch=getc(fin);

if(ch=='=')

{

token[1]=ch;token[2]='\0';

ch=getc(fin);

}

else

token[1]='\0';

fprintf(fout,"%s\t%s\n",token,token);

}

else if(ch=='/')

{

ch=getc(fin);

if(ch=='*')

{ char ch1;

ch1=getc(fin);

do

{ch=ch1;ch1=getc(fin);}

while((ch!='*' || ch1!='/')&&ch1!=EOF);

ch=getc(fin);

}

else

{

token[0]='/'; token[1]='\0';

fprintf(fout,"%s\t%s\n",token,token);

}

}

else

{

token[0]=ch;token[1]='\0';

ch=getc(fin);

es=3;

fprintf(fout,"%s\t%s\n","ERROR",token);

}

}

fclose(fin);

fclose(fout);

return(es);

}

//TESTmain.cpp

//主程序

#include

#include

extern int TESTscan();

char Scanin[300],Scanout[300];

FILE *fin,*fout;

void main()

{

int es=0;

es=TESTscan();

if (es>0) printf("词法分析有错,编译停止!");

else printf("词法分析成功!\n");

}