#include
#include
#include
#include
#define max 20
void scaner();
int digit(char ch);
int letter(char ch);
char **variable;//定义用户自变量信息表
FILE *fpw;
FILE *fprt;
void P();//递归下降主控制程序
void Parse();
void lrparser();//语句块 B
void yucu();//语句串 SS
void statement();//语句 S
void Equal();//赋值语句
void if_else();//条件语句
void do_while();//循环语句
int Condition();//条件
char * expression();//表达式
char * term();//项
char * factor();//因子
void error();
int i_quad = 0, k = 0, i_err = 0, i_erter = 0;
typedef struct quaternion{
char res[max];
char argv1[max];
char op[max];
char argv2[max];
}quad;
quad * pQuad;
int index,nSuffix;//四元式编号，临时变量编号
int state;
void emit(char *op,char *ag1,char*ag2,char *result);
char *Newtemp(void);
int merge(int p1,int p2);
void bp(int p,int t);
char prog[1000], token[8];
char ch;
int syn = 0, p, Q = 0, ERROR = 0;
double sum = 0;
int main()
{
Q = 0; ERROR = 0; syn = 0; sum = 0;
int j;
p = 0;
//printf("please input string:\n");
/*do{
ch = getchar();
prog[p] = ch;
p++;
} while (ch != '#');*/
if((fprt=fopen("C:\\Users\\hujiaxuan\\Documents\\codeblocksProject\\yuyi\\read.txt","rt"))==NULL){
printf("\open file error!");
exit(1);
}
while(ch!=EOF&&ch!='#'){
ch=fgetc(fprt);
prog[p]=ch;
p++;
putchar(ch);
}
fclose(fprt);
j = p;
p = 0;
while (p0 && syn < 10) Q++;
else Q = 0;
break;
}
}
p = 0;
Parse();
}
void scaner()
{
int n, i = 0;
char *rwtab[9] = { "main", "int", "float", "double", "char", "if", "else", "do", "while" };
for (n = 0; n<8; n++)
token[n] = '\0';
ch = prog[p];
//去除多余空格 Tab 换行
while (ch == ' ' || ch == '\n' || ch == ' ')
{
if (ch == '\n') i_erter++;
p++;
ch = prog[p];
}
//去除注释//
if (ch == '/'&&prog[p + 1] == '/')
{
while (ch != '\n')
{
p = p + 2;
ch = prog[p];
}
p++;
ch = prog[p];
}
//去除多余空格 Tab 换行
while (ch == ' ' || ch == '\n' || ch == ' ')
{
if (ch == '\n') i_erter++;
p++;
ch = prog[p];
}
//去除注释/*
if (ch == '/'&&prog[p + 1] == '*')
{
while ((ch == '*'&&prog[p + 1] == '/') != 1)
{
p++;
ch = prog[p];
}
p = p + 2;
ch = prog[p];
}
//去除多余空格 Tab 换行
while (ch == ' ' || ch == '\n' || ch == ' ')
{
if (ch == '\n') i_erter++;
p++;
ch = prog[p];
}
if (letter(ch))
{
while (letter(ch) || digit(ch))
{
token[i] = ch;
i++;
p++;
ch = prog[p];
}
syn = 10;
Q = 1;
for (n = 0; n<9; n++)
if (strcmp(token, rwtab[n]) == 0)
{
syn = n + 1;
break;
}
if (strcmp(token, "then") == 0)
{
syn = 40;
}
}
else if (digit(ch) || ch == '+' || ch == '-')
{
if (ch == '+' || ch == '-')
if (digit(prog[p + 1]) && Q == 0){
token[0] = ch;
i++;
p++;
ch = prog[p];
}
else{
if (ch == '+') { syn = 22; token[0] = ch; p++; Q = 0; }
if (ch == '-') { syn = 23; token[0] = ch; p++; Q = 0; }
}
if (digit(ch))
{
syn = 20;
Q = 1;
while (digit(ch))
{
token[i] = ch;
i++;
p++;
ch = prog[p];
}
sum = atoi(token);
if (ch == '.'&&syn == 20)
{
token[i] = ch;
p++;
ch = prog[p];
if (digit(ch))
{
while (digit(ch))
{
i++;
token[i] = ch;
p++;
ch = prog[p];
}
i++;
sum = atof(token);
}
else syn = -1;
}
if (ch == 'e'&&syn == 20)
{
token[i] = ch; i++;
p++; ch = prog[p];
token[i] = ch; i++;
p++; ch = prog[p];
if ((prog[p - 1] == '-' || prog[p - 1] == '+') && digit(ch))
{
while (digit(ch))
{
token[i] = ch;
i++;
p++;
ch = prog[p];
}
sum = atof(token);
}
else syn = -1;
}
}
}
else{
Q = 0;
switch (ch)
{
case '*':syn = 24; token[0] = ch; p++; break;
case '/':syn = 25; token[0] = ch; p++; break;
case '(':syn = 26; token[0] = ch; p++; break;
case ')':syn = 27; token[0] = ch; p++; break;
case '{':syn = 28; token[0] = ch; p++; break;
case '}':syn = 29; token[0] = ch; p++; break;
case ':':syn = 30; token[0] = ch; p++; break;
case ';':syn = 31; token[0] = ch; p++; break;
case '>':
p++;
ch = prog[p];
if (ch == '=')
{
syn = 33;
token[0] = '>'; token[1] = '=';
p++;
}
else syn = 32; token[0] = '>';
break;
case '<':
p++;
ch = prog[p];
if (ch == '=')
{
syn = 35;
token[0] = '<'; token[1] = '=';
p++;
}
else syn = 34; token[0] = '<';
break;
case '=':
p++;
ch = prog[p];
if (ch == '=')
{
syn = 36;
token[0] = '='; token[1] = '=';
p++;
}
else syn = 21; token[0] = '=';
break;
case '!':
p++;
ch = prog[p];
if (ch == '=')
{
syn = 37;
token[0] = '!'; token[1] = '=';
p++;
}
break;
case '#':syn = 0; token[0] = '#'; p++; break;
default: syn = -1; p++;
break;
}
}
}
int letter(char ch)
{
if ((ch >= 'a'&&ch <= 'z') || (ch >= 'A'&&ch <= 'Z'))
return 1;
return 0;
}
int digit(char ch)
{
if (ch >= '0'&&ch <= '9')
return 1;
return 0;
}
void P()
{
int nchain;
scaner();
if(syn==1){
scaner();
if(syn==26){
scaner();
if(syn==27){
scaner();
lrparser();
}else error();
}else error();
}else error();
}
void lrparser(){//语句块
if(syn==28){
scaner();
yucu();
if(syn==29) scaner();
else error();
}else error();
}
void yucu(){//语句串
statement();
if (syn==31) scaner();
while(syn!=29){
statement();
if(syn==31) scaner();
else error();
}
}
void statement(){//语句
if(syn==10) Equal();
else if(syn==6) if_else();
else if(syn==8) do_while();
else error();
}
void Equal(){ //赋值语句
char temp[max];
char *place;
if(syn==10){
strcpy(temp,token);
scaner();
if(syn==21){
scaner();
place=expression();
emit("=",place,"",temp);
}else error();
}else error();
}
void if_else(){
int m,n;
if(syn==6){
scaner();
m=Condition();
lrparser();
if(syn==7){
scaner();
n=index;
emit("goto","","","0");
itoa(index,pQuad[m].res,10);
lrparser();
itoa(index,pQuad[n].res,10);
}else{
itoa(index,pQuad[m].res,10);
}
}
}
int Condition(){ //if_else 语句中的条件判断
char ntc[max];
char op[max],optmp[max],*place1,*place2;
int m;
place1=expression();
if(syn>31&&syn<38){
sprintf(op,"%s",token);
scaner();
place2=expression();
sprintf(optmp,"goto %s",op);
itoa(index+2,ntc,10);
m=index+1;
emit(optmp,place1,place2,ntc);
emit("goto","","","0");//"0"标记需要回填
}else error();
return m;//返回需要回填的四元式序列号
}
int Condition2(){ //do_while语句中的条件判断
char ntc[max];
char op[max],optmp[max],*place1,*place2;
int m;
place1=expression();
if(syn>31&&syn<38){
sprintf(op,"%s",token);
scaner();
place2=expression();
sprintf(optmp,"goto %s",op);
itoa(index+2,ntc,10);
m=index;
emit(optmp,place1,place2,"0");//"0"标记需要回填
emit("goto","","",ntc);
}else error();
return m;//返回需要回填的四元式序列号
}
void do_while(){
int k,b;
if(syn==8){
scaner();
k=index;
lrparser();
if(syn==9){
scaner();
b=Condition2();
itoa(k,pQuad[b].res,10);
}else error();
}else error();
}
char * expression()
{
char op[max],*place1,*place2;
char *place=(char *)malloc(max);
place=place1=term();
while(syn==22||syn==23){
sprintf(op,"%s",token);
scaner();
place2=term();
place=Newtemp();
emit(op,place1,place2,place);
place1=place;
}
return place;
}
char * term()
{
char op[max],*place1,*place2;
char *place;
place=place1=factor();
while(syn==24||syn==25){
sprintf(op,"%s",token);
scaner();
place2=factor();
place=Newtemp();
emit(op,place1,place2,place);
place1=place;
}
return place;
}
char * factor()
{
char * place = (char *)malloc(max);
if(syn==10){
sprintf(place,"%s",token);
scaner();
}else if(syn==20){
sprintf(place,"%g",sum);
scaner();
}else if(syn==26){
scaner();
place=expression();
if(syn==27){
scaner();
}else error();
}else error();
return place;
}
void emit(char *op,char * argv1,char * argv2,char * result){
sprintf(pQuad[index].op,"%s",op);
sprintf(pQuad[index].argv1,"%s",argv1);
sprintf(pQuad[index].argv2,"%s",argv2);
sprintf(pQuad[index].res,"%s",result);
index++;
}
char *Newtemp(){
char * tmpID=(char *)malloc(max);
sprintf(tmpID,"T%d",++nSuffix);
return tmpID;
}
void printQuad(){
int n;
printf("four yuan List:\n");
for(n=1;n
