编译原理：语法分析程序
一、目的
编写词法分析和语法分析程序，并对某一由TEST语言编写的源程序进行分析得到词法分析和语法分析结果。
二、源程序
#include
#include//ctype.h是C标准函数库中的头文件，定义了一批C语言字符分类函数，用于测试字符是否属于特定的字符类别
#include//conio.h库文件定义了通过控制台进行数据输入和数据输出的函数，主要是一些用户通过按键盘产生的对应操作
#include
#include
#define keywordSum 9
//字符串指针数组保存保留字（扩充到9个char）（改动）
char *keyword[keywordSum] = { "if","else","for","while","do","read","write","char","int" };//return,switch,case,break,continue
//纯单分界符（改动）
char singleword[50] = { '+','-','*','(',')','{','}',',',';',':' ,'.'};
//双分界符的首字母
char doubleword[10] = { '>','<','=','!' };
//输入、输出文件名
char Scanin[300], Scanout[300],Result[300];
//指向文件的指针
FILE *fin, *fout,*fp,*fr;
char token[20], token1[40];//token保存单词符号，token1保存单词值
//函数声明
int TESTscan();
int TESTparse();
int program();
int declaration_list();
int statement_list();
int if_stat();
int while_stat();
int for_stat();
int write_stat();
int read_stat();
int declaration_stat();
int compound_stat();
int expression_stat();
int statement();
int expression();
int bool_expr();
int additive_expr();
int term();
int factor();
//词法分析函数
int TESTscan() {//返回1，输入文件错误；返回2，输出文件错误；返回3，非法符号；
char ch;//每次读入的字符
char token[40];//保存识别的单词
int es = 0, j, n;//es为0表示无错误
printf("请输入源程序文件名（包括路径）：");
scanf("%s", Scanin);
getchar();
printf("请输入词法分析输出文件名（包括路径）：");
scanf("%s", Scanout);
getchar();
if ((fin = fopen(Scanin, "r")) == NULL)
{
printf("\n打开词法分析输入文件出错！\n");
return(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);//从文件中读取字符
while (ch != EOF)//文件未读完时
{
while (ch == ' ' || ch == '\n' || ch == '\t')//滤过空格和转义字符
ch = getc(fin);
//判断是否是识别符还是保留字
if (ch >= 'a'&&ch <= 'z' || ch >= 'A'&&ch <= 'Z' || ch == '_')//（扩充一个下划线）（改动）
{
token[0] = ch;
j = 1;
ch = getc(fin);
while (ch >= 'a'&&ch <= 'z' || ch >= 'A'&&ch <= 'Z' || ch == '_' || ch >= '0'&&ch <= '9')
{
token[j++] = ch;
ch = getc(fin);
}
token[j] = '\0';
//查是否为保留字
n = 0;
while ((n= keywordSum)//不是保留字
fprintf(fout, "%s\t%s\n", "ID", token);
else
fprintf(fout, "%s\t%s\n", token, token);
}
//数字
else if (ch >= '0'&&ch <= '9')
{
token[0] = ch;
j = 1;
ch = getc(fin);
while (ch >= '0'&&ch <= '9')
{
token[j++] = ch;
ch = getc(fin);
}
token[j] = '\0';
fprintf(fout, "%s\t%s\n", "NUM", token);
}
//纯单界符
else if (strchr(singleword, ch) > 0)//查找字符串s中首次出现字符ch的位置,返回首次出现ch的位置的指针，如果s中不存在ch则返回NULL。
{
token[0] = ch;
token[1] = '\0';
ch = getc(fin);
fprintf(fout, "%s\t%s\n", token, token);
}
//双分界符
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);
}
//注释处理
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);
}
}
//错误处理
else
{
token[0] = ch;
token[1] = '\0';
ch = getc(fin);//跳过错误，识别下一个单词。
es = 3;
fprintf(fout, "%s\t%s\n", "ERROR", token);
}
}
fclose(fin);
fclose(fout);
return(es);
}
//语法分析函数
int TESTparse()
{
int es = 0;
if ((fp = fopen(Scanout, "r")) == NULL)
{
printf("\n打开词法分析输出文件出错！\n");
es=10;
}
printf("请输入语法分析输出文件名（包括路径）：");
scanf("%s", Result);
if ((fr = fopen(Result, "w")) == NULL)
{
printf("\n打开语法分析输出文件出错！\n");
return(8);
}
if (es == 0)
es = program();
printf("\n语法分析结果如下：\n");
switch (es)
{
case 0:
printf("语法分析成功！\n");
fprintf(fr,"\n%s\n","语法分析成功！\n");
break;
case 1:
printf("缺少{\n");
fprintf(fr, "\n%s\n", "缺少{\n");
break;
case 2:
printf("缺少}\n");
fprintf(fr, "\n%s\n", "缺少}\n");
break;
case 3:
printf("缺少识别符\n");//declaration_stat()
fprintf(fr, "\n%s\n", "缺少识别符\n");
break;
case 4:
printf("缺少分号\n");
fprintf(fr, "\n%s\n", "缺少分号\n");
break;
case 5:
printf("缺少(\n");
fprintf(fr, "\n%s\n", "缺少（\n");
break;
case 6:
printf("缺少)\n");
fprintf(fr, "\n%s\n", "缺少）\n");
break;
case 7:
printf("缺少操作数\n");//factor()
fprintf(fr, "\n%s\n", "缺少操作数\n");
break;
case 8:
printf("\n打开语法分析输出文件出错！\n");
fprintf(fr, "\n%s\n", "\n打开语法分析输出文件出错！\n");
break;
case 10:
printf("\n打开词法分析输出文件出错！\n");
fprintf(fr, "\n%s\n", "\n打开词法分析输出文件出错！\n");
break;
}
fclose(fp);
fclose(fr);
return(es);
}
//程序 子函数
int program()
{
int es = 0;
fscanf(fp,"%s\t%s\n",&token,&token1);//“读文件”函数
fprintf(fr, "%s\t%s\n", &token, &token1);
if (strcmp(token, "{"))//相等时，返回“0”，不执行该语句，比较的是token
{
es = 1;
return es;
}
fscanf(fp, "%s\t%s\n", &token, &token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
es = declaration_list();//fscanf和printf操作包含在子函数中
if (es > 0)
return(es);
es = statement_list();
if (es > 0)
return(es);
if (strcmp(token, "}"))
{
es = 2;
return(es);
}
return(es);
}
int declaration_list()
{
int es = 0;
while ((strcmp(token,"int")==0)||(strcmp(token,"char")==0))//扩充了char型
{
es = declaration_stat();
if (es > 0)
return(es);
}
return(es);
}
int declaration_stat()
{
int es = 0;
fscanf(fp, "%s\t%s\n", &token, &token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
if (strcmp(token, "ID"))
return(es=3);//缺少识别符
fscanf(fp, "%s\t%s\n", &token, &token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
if (strcmp(token, ";"))
return(es = 4);
fscanf(fp, "%s\t%s\n", &token, &token1);//读下一个token，用于判断declaration_list()的循环条件
fprintf(fr, "%s\t%s\n", &token, &token1);
return(es);
}
int statement_list()
{
int es = 0;
while (strcmp(token, "}"))//当扫描到token是“}”时，while（0）,此语句不执行，即不再有statement了。program结束！
//结合program()函数来看
{
es = statement();
if (es > 0)
return(es);
}
return(es);
}
int compound_stat()
{
int es = 0;
fscanf(fp, "%s\t%s\n", &token, &token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
es = statement_list();
return(es);
}
int statement()
{
int es = 0;
if (es == 0 && strcmp(token, "if") == 0)
{
fprintf(fr, "\n%s\n", "\n---if语句---\n");
printf("\n源程序存在if语句\n");
es = if_stat();
}
if (es == 0 && strcmp(token, "while") == 0)
{
fprintf(fr, "\n%s\n", "\n---while语句---\n");
printf("\n源程序存在while语句\n");
es = while_stat();
}
if (es == 0 && strcmp(token, "for") == 0)
{
fprintf(fr, "\n%s\n", "\n---for语句---\n");
printf("\n源程序存在for语句\n");
es = for_stat();
}
if (es == 0 && strcmp(token, "read") == 0)
{
fprintf(fr, "\n%s\n", "\n---read语句---\n");
printf("\n源程序存在read语句\n");
es = read_stat();
}
if (es == 0 && strcmp(token, "write") == 0)
{
fprintf(fr, "\n%s\n", "\n---write语句---\n");
printf("\n源程序存在write语句\n");
es = write_stat();
}
if (es == 0 && strcmp(token, "{") == 0)
{
fprintf(fr, "\n%s\n", "\n---复合语句---\n");
printf("\n源程序存在复合语句\n");
es = compound_stat();
}
if (es == 0 && strcmp(token, "ID") == 0 || strcmp(token, "NUM") == 0 || strcmp(token, "(") == 0)
{
printf("\n源程序存在表达式语句\n");
es = expression_stat();
}
return(es);
}
int if_stat(){
int es=0;
fscanf(fp,"%s\t%s\n",&token,&token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
if(strcmp(token,"("))
return(es=5);
fscanf(fp,"%s\t%s\n",&token,&token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
es=expression();
if(es>0)
return(es);
if(strcmp(token,")"))
return(es=6);
fscanf(fp,"%s\t%s\n",&token,&token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
es=statement();
if(es>0)
return(es);
if(strcmp(token,"else")==0)
{
fscanf(fp,"%s\t%s\n",&token,&token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
es=statement();
if(es>0)
return(es);
}
return(es);
}
int while_stat()
{
int es = 0;
fscanf(fp, "%s\t%s\n", &token, &token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
if (strcmp(token, "("))
return(es = 5);
fscanf(fp, "%s\t%s\n", &token, &token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
es = expression();
if (es>0)
return(es);
if (strcmp(token, ")"))
return(es = 6);
fscanf(fp, "%s\t%s\n", &token, &token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
es = statement();
return(es);
}
int for_stat()
{
int es = 0;
fscanf(fp, "%s\t%s\n", &token, &token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
if (strcmp(token, "("))
return(es = 5);
fscanf(fp, "%s\t%s\n", &token, &token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
es = expression();
if (es>0)
return(es);
if (strcmp(token, ";"))
return(es = 4);
fscanf(fp, "%s\t%s\n", &token, &token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
es = expression();
if (es>0)
return(es);
if (strcmp(token, ";"))
return(es = 4);
fscanf(fp, "%s\t%s\n",&token, &token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
es = expression();
if (es>0)
return(es);
if (strcmp(token, ")"))
return(es = 6);
fscanf(fp, "%s\t%s\n", &token, &token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
es = statement();
return(es);
}
int write_stat()
{
int es = 0;
fscanf(fp, "%s\t%s\n", &token, &token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
es = expression();
if (es>0)
return(es);
if (strcmp(token, ";"))
return(es = 4);
fscanf(fp, "%s\t%s\n", &token, &token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
return(es);
}
int read_stat()
{
int es = 0;
fscanf(fp, "%s\t%s\n", &token, &token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
if (strcmp(token, "ID"))
return(es = 3);
fscanf(fp, "%s\t%s\n", &token, &token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
if (strcmp(token, ";"))
return(es = 4);
fscanf(fp, "%s\t%s\n", &token, &token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
return (es);
}
int expression_stat()
{
int es = 0;
if (strcmp(token, ";") == 0)
{
fscanf(fp, "%s\t%s\n", &token, &token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
return(es);
}
es = expression();
if (es > 0)
return(es);
if (es == 0 && strcmp(token, ";") == 0)
{
fscanf(fp, "%s\t%s\n", &token, &token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
return(es);
}
else
{
es = 4;
return(es);//缺少；
}
}
int expression()
{
int es = 0, fileadd;
char token2[20], token3[40];
if (strcmp(token, "ID") == 0)
{
fileadd = ftell(fp);
fscanf(fp, "%s\t%s\n", &token2, &token3);
fprintf(fr, "%s\t%s\n", &token2, &token3);
if (strcmp(token2, "=") == 0)
{
fscanf(fp, "%s\t%s\n", &token, &token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
es = bool_expr();
if (es>0)
return(es);
}
else
{
fseek(fp, fileadd, 0);
es = bool_expr();
if (es>0)
return(es);
}
}
else
es = bool_expr();
return(es);
}
int bool_expr()
{
int es = 0;
es = additive_expr();
if (es>0)
return(es);
if (strcmp(token, ">") == 0 || strcmp(token, ">=") == 0 || strcmp(token, "<") == 0 || strcmp(token, "<=") == 0 || strcmp(token, "==") == 0 || strcmp(token, "!=") == 0)
{
fscanf(fp, "%s\t%s\n", &token, &token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
es = additive_expr();
if (es>0)
return(es);
}
return(es);
}
int additive_expr(){
int es = 0;
es = term();
if (es>0)
return(es);
while (strcmp(token, "+") == 0 || strcmp(token, "-") == 0)
{
fscanf(fp, "%s\t%s\n", &token, &token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
es = term();
if (es>0) return(es);
}
return(es);
}
int term(){
int es = 0;
es = factor();
if (es>0)
return(es);
while (strcmp(token, "*") == 0 || strcmp(token, "/") == 0)
{
fscanf(fp, "%s\t%s\n", &token, &token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
es = factor();
if (es>0)
return(es);
}
return(es);
}
int factor(){
int es = 0;
if (strcmp(token, "(") == 0)
{
fscanf(fp, "%s\t%s\n", &token, &token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
es = expression();
if (es>0)
return(es);
if (strcmp(token, ")"))
return(es = 6);
fscanf(fp, "%s\t%s\n", &token, &token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
}
else
{
if (strcmp(token, "ID") == 0 || strcmp(token, "NUM") == 0)
{
fscanf(fp, "%s\t%s\n", &token, &token1);
fprintf(fr, "%s\t%s\n", &token, &token1);
return(es);
}
else
{
es = 7;
return(es);
}
}
return(es);
}
//主函数
void main()
{
int es = 0;
es = TESTscan();
switch (es) {//switch语句详细解释错误情况
case 0:
printf("词法分析成功！\n");
break;
case 1:
printf("输入文件有错，编译停止！\n");
break;
case 2:
printf("输出文件有错，编译停止！\n");
break;
case 3:
printf("存在非法符号，编译停止！\n");
break;
}
if (es == 0)
{
es = TESTparse();
if (es == 0)
printf("语法分析成功！\n");
else
printf("语法分析错误！\n");
}
system("pause");
}