编译原理第三版附带的实验源码

Scanner:

#include

#include

#include

#define _KEY_WORD_END "waiting for your expanding"

typedef struct

{

int typenum;

char * word;

} WORD;

char input[255];

char token[255]="";

int p_input;

int p_token;

char ch;

char* KEY_WORDS[]={"main","int","char","if","else","for","while",_KEY_WORD_END}; WORD* scaner();

void main()

{

int over=1;

WORD* oneword=new WORD;

printf("Enter Your words(end with $):");

scanf("%[^$]s",input);

p_input=0;

printf("Your words:\n%s\n",input);

while(over<1000&&over!=-1){

oneword=scaner();

if(oneword->typenum<1000)

printf("(%d,%s)",oneword->typenum,oneword->word);

over=oneword->typenum;

}

printf("\npress # to exit:");

scanf("%[^#]s",input);

}

char m_getch(){

ch=input[p_input];

p_input=p_input+1;

return (ch);

}

void getbc(){

while(ch==' '||ch==10){

ch=input[p_input];

p_input=p_input+1;

}

}

void concat(){

token[p_token]=ch;

p_token=p_token+1;

token[p_token]='\0';

}

int letter(){

if(ch>='a'&&ch<='z'||ch>='A'&&ch<='Z')return 1;

else return 0;

}

int digit(){

if(ch>='0'&&ch<='9')return 1;

else return 0;

}

int reserve(){

int i=0;

while(strcmp(KEY_WORDS[i],_KEY_WORD_END)){ if(!strcmp(KEY_WORDS[i],token)){

return i+1;

}

i=i+1;

}

return 10;

}

void retract(){

p_input=p_input-1;

}

char* dtb(){

return NULL;

}

WORD* scaner(){

WORD* myword=new WORD;

myword->typenum=10;

myword->word="";

p_token=0;

m_getch();

getbc();

if(letter()){

while(letter()||digit()){

concat();

m_getch();

}

retract();

myword->typenum=reserve();

myword->word=token;

return(myword);

}

else if(digit()){

while(digit()){

concat();

m_getch();

}

retract();

myword->typenum=20;

myword->word=token;

return(myword);

}

else switch(ch){

case '=': m_getch();

if (ch=='='){

myword->typenum=39;

myword->word="==";

return(myword);

}

retract();

myword->typenum=21;

myword->word="=";

return(myword);

break;

case '+': myword->typenum=22;

myword->word="+";

return(myword);

break;

case '-': myword->typenum=23;

myword->word="-";

return(myword);

break;

case '*': myword->typenum=24;

myword->word="*";

return(myword);

break;

case '/': myword->typenum=25;

myword->word="/";

return(myword);

break;

case '(': myword->typenum=26;

myword->word="(";

return(myword);

break;

case ')': myword->typenum=27;

myword->word=")";

return(myword);

break;

case '[': myword->typenum=28;

myword->word="[";

return(myword);

break;

case ']': myword->typenum=29;

myword->word="]";

return(myword);

break;

case '{': myword->typenum=30;

myword->word="{";

return(myword);

break;

case '}': myword->typenum=31;

myword->word="}";

return(myword);

break;

case ',': myword->typenum=32;

myword->word=",";

return(myword);

break;

case ':': myword->typenum=33;

myword->word=":";

return(myword);

break;

case ';': myword->typenum=34;

myword->word=";";

return(myword);

break;

case '>': m_getch();

if (ch=='='){

myword->typenum=37;

myword->word=">=";

return(myword);

}

retract();

myword->typenum=35;

myword->word=">";

return(myword);

break;

case '<': m_getch();

if (ch=='='){

myword->typenum=38;

myword->word="<=";

return(myword);

}

retract();

myword->typenum=36;

myword->word="<";

return(myword);

break;

case '!': m_getch();

if (ch=='='){

myword->typenum=40;

myword->word="!=";

return(myword);

}

retract();

myword->typenum=-1;

myword->word="ERROR";

return(myword);

break;

case '\0': myword->typenum=1000;

myword->word="OVER";

return(myword);

break;

default: myword->typenum=-1;

myword->word="ERROR";

return(myword);

}

}

Parsing:

#include

#include

#include

int syn,p_input,p_token,kk;

char ch;

char input[100];

char token[100]="";

char* key_words[]={"begin","if","then","while","do","end"}; int expression();

void m_getch();

int letter();

int digit();

int compare();

void c_token();

void scaner();

void main()

{

FILE *fin;

char buffer[100];

int size;

if((fin=fopen("test.txt","r"))==NULL)

{

printf("Cannot open the file!\n");

exit(-1);

}

fin=fopen("test.txt","r");

while(fgets(buffer,100,fin)!=NULL)

{

strcat(input,buffer);

}

lrparser();

printf("\npress # to exit:\n");

scanf("%[^#]",input);

fclose(fin);

}

{ scaner();

if(syn==1)

{

scaner();

yucu();

if(syn==6)

{

scaner();

if((syn==0)&&(kk==0))

{

printf("Success\n");

return 1;

}

}

else

{

if(kk!=1)

printf("no end error\n");

kk=1;

return 0;

}

}

else

{

printf("no begin error\n");

kk=1;

return 0;

}

}

int yucu()

{

statement();

while (syn==29)

{

scaner();

statement();

}

return 1;

}

{

p_token=0;

m_getch();

while(ch==' '||ch==10)

m_getch();

if(letter())

{

while(letter()||digit())

{

c_token();

m_getch();

}

p_input--;

syn=compare();

}

else if(digit())

{

while(digit())

{

c_token();

m_getch();

}

p_input--;

syn=11;

}

else switch(ch)

{

case '=': c_token();

m_getch();

if(ch=='=')

{

syn=24;

c_token();

}

else

{

p_input--;

syn=21;

}

break;

case '<': c_token();

m_getch();

if(ch=='=')

syn=25;

c_token();

}

else if(ch=='>')

{

syn=26;

c_token();

}

else

{ p_input--;

syn=22;

}

break;

case '>': c_token();

m_getch();

if(ch=='=')

{

syn=27;

c_token();

}

else

{

p_input--;

syn=23;

}

break;

case '+': syn=13;c_token();break;

case '-': syn=14;c_token();break;

case '*': syn=15;c_token();break;

case '/': syn=16;c_token();break;

case '(': syn=17;c_token();break;

case ')': syn=18;c_token();break;

case '{': syn=19;c_token();break;

case '}': syn=20;c_token();break;

case ';': syn=29;c_token();break;

case '#': syn=0;break;

default : syn=-1;c_token();

}

}

void m_getch()

{

ch=input[p_input];

p_input++;

}

void c_token()

{

token[p_token]=ch;

p_token++;

token[p_token]='\0';

}

int compare()

{

int n;

for(n=0;n<6;n++)

{

if(strcmp(key_words[n],token)==0)

return n+1;

}

return 10;

}

int letter(){

if(ch>='a'&&ch<='z'||ch>='A'&&ch<='Z')return 1;

else return 0;

}

int digit(){

if(ch>='0'&&ch<='9')return 1;

else return 0;

}

int expression()

{

term();

while (syn==13||syn==14)

{

scaner();

term();

}

return 1;

}

int factor()

{

if(syn==10||syn==11)

scaner();

else if(syn==17)

{

scaner();

expression();

if (syn==18)

{

scaner();

}

else { printf("输入错误\n");kk=1;return 0;} }

else {printf("输入表达式错误\n");kk=1;return 0;} return 1;

}

int term()

{

factor();

while(syn==15||syn==16)

{

scaner();

factor();

}

return 1;

}

int statement()

{

if(syn==10)

{

scaner();

if (syn==21)

{

scaner();

expression();

}

else {printf("输入赋值错误\n");kk=1;} }

else {printf("输入语句错误\n");kk=1;}

return 1;

}