Lexical-analysis/lexi.cpp at master · leeonfield/Lexical-analysis · GitHub

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#include<stdio.h>
#include<ctype.h>
#include<conio.h>
#include<stdlib.h>
#include<string.h>
int TESTparse();
int program();

int statement();
int statement_list();

int expression();
int expression_stat();

int declaration_stat();
int declaration_list();

int if_stat();
int for_stat();
int read_stat();
int write_stat();
int while_stat();
int compound_stat();

int term();
int factor();
int bool_expr();
int additive_expr();

char token[20], token1[40];//token保存单词符号，token1保存单词值
extern char Scanout[300];//保存词法分析输出文件名
FILE *fp;//用于指向输入文件的指针

int TESTparse()
{
	int es = 0;
	if ((fp = fopen(Scanout, "r")) == NULL)
	{
		printf("\n Open %s error !\n", Scanout);
		es = 10;
	}
	if (es == 0)
	{
		es = program();
	}
	printf("=========Result!=========\n");
	switch (es)
	{
		case 0:printf("Grammar analysis succeed!\n"); break;
		case 10:printf("Open %s error!\n", Scanout); break;
		case 1:printf("Lack {    \n"); break;
		case 2:printf("Lack }    \n"); break;
		case 3:printf("Lack !    \n"); break;
		case 4:printf("Lack ;   \n"); break;
		case 5:printf("Lack (    \n"); break;
			case 6:printf("Lack )    \n"); break;
	case 7:printf("Lack operand \n"); break;//缺少操作数
}
fclose(fp);
return (es);
}


//<程序>::={<声明序列><语句序列>}
//program::=={<declaration_list><statement_list>}
int program()
{
	int es = 0;
	fscanf(fp, "%s%s\n", &token, &token1);
	printf("%s	%s\n", token, token1);
	if (strcmp(token, "{"))
	{
		es = 1;
		return (es);
	}
	fscanf(fp, "%s%s\n", &token, &token1);
	printf("%s	%s\n", token, token1);
	es = declaration_list();
	if (es > 0)
	{
		return (es);
	}
	es = statement_list();
	if (es > 0)
	{
		return (es);
	}
	if (strcmp(token, "}"))
	{
		es = 2;
		return (es);
	}
	return (es);
}


//<声明序列>::=<声明序列><声明语句>|<声明语句>
//<declaration_list>:: = <declaration_list><declaration_stat> | 改成<declaration_list>:: = {<declaration_stat> }

int declaration_list()
{
	int es = 0;
	while (strcmp(token, "int") == 0)
	{
		es = declaration_stat();
		if (es > 0)
		{
			return (es);
		}
	}
	return (es);
}


//<声明语句>::=int<变量>
//<declaration_stat>:: = int ID;
int  declaration_stat()
{
	int es = 0;

	fscanf(fp, "%s%s\n", &token, &token1);
	printf("%s	%s\n", token, token1);
	if (strcmp(token, "ID"))
	{
		return (es = 3);//不是标识符
	}
	fscanf(fp, "%s%s\n", &token, &token1);
	printf("%s	%s\n", token, token1);
	if (strcmp(token, ";"))
	{
		return (es = 4);//不是标识符
	}
	fscanf(fp, "%s%s\n", &token, &token1);
	printf("%s	%s\n", token, token1);
	return (es);
}

//<语句序列>::=<语句序列><语句>|
//<statement_list>::=<statement_list><statement>|       改成     <statement_list>::={<statement>}
int statement_list()
{
	int es = 0;
	while (strcmp(token, "}"))
	{
		es = statement();
		if (es > 0)
		{
			return (es);
		}
	}
	return (es);
}


//<语句>::=<if语句>|<while语句>|<for语句>|<read语句>|<write语句>|<复合语句>|<表达式语句>

//<statement>::=<if_stat>|<while_stat>|<for_stat>|<compound_stat>|<expression_stat>
int statement()
{
	int es = 0;
	if (es == 0 && strcmp(token, "if") == 0)
	{
		es = if_stat();
	}

	if (es == 0 && strcmp(token, "while") == 0)
	{
		es = while_stat();
	}

	if (es == 0 && strcmp(token, "for") == 0)
	{
		es = for_stat();
	}

	if (es == 0 && strcmp(token, "read") == 0)
	{
		es = read_stat();
	}

	if (es == 0 && strcmp(token, "write") == 0)
	{
		es = write_stat();
	}

	if (es == 0 && strcmp(token, "{") == 0)
	{
		es = compound_stat();						//复合语句
	}

	if (es == 0 && strcmp(token, "ID") == 0 || strcmp(token, "NUM") == 0 || strcmp(token, "(") == 0)
	{
		es = expression_stat();
	}
	return (es);
}


//<if语句>::=if(<表达式>)<语句>[else<语句>]
//<if_stat>:: = if (<expression>)<statement>[else<statement>]

int if_stat()
{
	int es = 0;
	fscanf(fp, "%s%s\n", &token, &token1);
	printf("%s	%s\n", token, token1);

	if (strcmp(token, "("))
	{
		return (es = 5);
	}
	fscanf(fp, "%s%s\n", &token, &token1);
	printf("%s	%s\n", token, token1);
	es = expression();
	if (es > 0)
	{
		return (es);
	}
	if (strcmp(token, ")"))
	{
		return (es = 6);
	}
	fscanf(fp, "%s%s\n", &token, &token1);
	printf("%s	%s\n", token, token1);
	es = statement();
	if (es > 0)
	{
		return (es);
	}
	if (strcmp(token, "else") == 0)
	{
		fscanf(fp, "%s%s\n", &token, &token1);
		printf("%s	%s\n", token, token1);
		es = statement();
		if (es > 0)
		{
			return (es);
		}
	}
	return (es);
}

//<while语句>::=while(<语句>)<语句>
//<while_stat>:: = while (<expr>)<statement>
int while_stat()
{
	int es = 0;
	fscanf(fp, "%s%s\n", &token, &token1);
	printf("%s	%s\n", token, token1);
	if (strcmp(token, "("))
	{
		return (es = 5);
	}
	fscanf(fp, "%s%s\n", &token, &token1);
	printf("%s	%s\n", token, token1);

	es = expression();
	if (es > 0)
	{
		return (es);
	}
	if (strcmp(token, ")"))
	{
		return (es = 6);
	}
	fscanf(fp, "%s%s\n", &token, &token1);
	printf("%s	%s\n", token, token1);

	es = statement();
	return (es);
}

//<for语句>::=for(<表达式>;<表达式>;<表达式>)<语句>
//<for_stat>:: = (<expression>; <expression>;<expression>)<statement>
int for_stat()
{
	int es = 0;

	fscanf(fp, "%s%s\n", &token, &token1);
	printf("%s	%s\n", token, token1);

	if (strcmp(token, "("))
	{
		return (es = 5);
	}

	fscanf(fp, "%s%s\n", &token, &token1);
	printf("%s	%s\n", token, token1);
	es = expression();
	if (es > 0)
	{
		return (es);
	}
	if (strcmp(token, ";"))
	{
		return (es = 4);
	}
	fscanf(fp, "%s%s\n", &token, &token1);
	printf("%s	%s\n", token, token1);
	es = expression();


	if (es > 0)
	{
		return (es);
	}
	if (strcmp(token, ";"))
	{
		return (es = 4);
	}
	fscanf(fp, "%s%s\n", &token, &token1);
	printf("%s	%s\n", token, token1);
	es = expression();

	if (es > 0)
	{
		return (es);
	}
	if (strcmp(token, ")"))
	{
		return (es = 6);
	}
	fscanf(fp, "%s%s\n", &token, &token1);
	printf("%s	%s\n", token, token1);
	es = statement();
	return (es);
}


//<write_语句>::=write<表达式>
//<write_stat>::=write<expression>
int write_stat()
{
	int es = 0;

	fscanf(fp, "%s%s\n", &token, &token1);
	printf("%s	%s\n", token, token1);

	es = expression();

	if (es > 0)
	{
		return (es);
	}
	if (strcmp(token, ";"))
	{
		return (es = 4);
	}
	fscanf(fp, "%s%s\n", &token, &token1);
	printf("%s	%s\n", token, token1);
	return (es);
}

//<read_语句>::=read<变量>;
//<read_stat>:: = read ID;
int read_stat()
{
	int es = 0;

	fscanf(fp, "%s%s\n", &token, &token1);
	printf("%s	%s\n", token, token1);

	if (strcmp(token, "ID"))
	{
		return (es = 3);
	}
	fscanf(fp, "%s%s\n", &token, &token1);
	printf("%s	%s\n", token, token1);

	if (strcmp(token, ";"))
	{
		return (es = 4);
	}
	fscanf(fp, "%s%s\n", &token, &token1);
	printf("%s	%s\n", token, token1);
	return (es);
}


//<复合语句>::={<语句序列>}
//<compound_Stat>:: = {<statement_list>}
int compound_stat()
{
	int es = 0;

	fscanf(fp, "%s%s\n", &token, &token1);
	printf("%s	%s\n", token, token1);

	es = statement_list();
	return (es);
}

//<表达式语句>::=<<表达式>>；|；
//<expression_stat>:: = <expression>; | ;
int expression_stat()
{
	int es = 0;

	if (strcmp(token, ";")==0)
	{
		fscanf(fp, "%s%s\n", &token, &token1);
		printf("%s	%s\n", token, token1);
		return (es);
	}
	es = expression();
	if (es > 0)
	{
		return (es);
	}
	if (es == 0 && strcmp(token, ";") == 0)
	{
		fscanf(fp, "%s%s\n", &token, &token1);
		printf("%s	%s\n", token, token1);
		return (es);
	}
	else
	{
		es = 4;
		return (es);
	}
}
//<表达式>::=<标识符>=<布尔表达式>|<布尔表达式>
//<expression>::=ID=<bool_expr>|<bool_expr>
int expression()
{
	int es = 0, fileadd;
	char token2[20], token3[40];
	if (strcmp(token, "ID") == 0)
	{
		fileadd = ftell(fp);//记住当前文件位置
		fscanf(fp, "%s%s\n", &token2, &token3);
		printf("%s	%s\n", token2, token3);
		if (strcmp(token2, "=") == 0)
		{
			fscanf(fp, "%s%s\n", &token, &token1);
			printf("%s	%s\n", token, token1);
			es = bool_expr();
			if (es > 0)
			{
				return (es);
			}
		}
		else
		{
			fseek(fp, fileadd, 0);//若非‘=’，则文件指针回到'='前的标识符
			printf("%s	%s\n", token, token1);
			es = bool_expr();
			if (es > 0)
			{
				return (es);
			}
		}
	}
	else
	{
		es = bool_expr();
	}
	return (es);
}


//<布尔表达式>::=<算术表达式>|<算术表达式>(>|<|>=|<=|==|!=)<算术表达式>
//<bool_expr>:: = <additive_expr> | <additive_expr>(> | < | >= | <= |= = | != )<additive_expr>
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%s\n", &token, &token1);
		printf("%s	%s\n", token, token1);
		es = additive_expr();
		if (es > 0)
		{
			return (es);
		}
	}
	return (es);
}


//<算术表达式>::=<项>{(+|-)<term>}
//<additive_expr>:: = <term>{(+|-)<term>}
int additive_expr()
{
	int es = 0;
	es = term();
	if (es > 0)
	{
		return (es);
	}
	while (strcmp(token, "+") == 0 || strcmp(token, "-") == 0)
	{
		fscanf(fp, "%s%s\n", &token, &token1);
		printf("%s	%s\n", token, token1);
		es = term();
		if (es > 0)
		{
			return (es);
		}
	}
	return (es);
}


//<项>::=<因子>{(*|/)<因子>}
//<term>:: = <factor>{(*|/)<factor>}
int term()
{
	int es = 0;
	es = factor();
	if (es > 0)
	{
		return (es);
	}
	while (strcmp(token, "*") == 0 || strcmp(token, "/") == 0)
	{
		fscanf(fp, "%s%s\n", &token, &token1);
		printf("%s	%s\n", token, token1);

		es = factor();
		if (es > 0)
		{
			return (es);
		}
	}
	return (es);
}


//<因子>::=(<表达式>)|<标识符>|<无符号整数>
//<factor>:: = (<expression>)|ID|NUM
int factor()
{
	int es = 0;
	if (strcmp(token, "(") == 0)
	{
		fscanf(fp, "%s%s\n", &token, &token1);
		printf("%s	%s\n", token, token1);
		es = expression();
		if (es > 0)
		{
			return (es);
		}
		if (strcmp(token, ")"))
		{
			return (es = 6);
		}
		fscanf(fp, "%s%s\n", &token, &token1);
		printf("%s	%s\n", token, token1);
	}
	else
	{
		if (strcmp(token, "ID") == 0 || strcmp(token, "NUM") == 0)
		{
			fscanf(fp, "%s%s\n", &token, &token1);
			printf("%s	%s\n", token, token1);
			return (es);
		}
		else
		{
			es = 7;
			return (es);
		}
	}
	return (es);
}