Lexical analyzer for simple C

This source code can be run in Linux !!! Recognize Decimals

 

# Include <unistd. h>
# Include <stdlib. h>
# Include <stdio. h>
# Include <string. h>
/* # Define null 0 */

/* Custom variables */
# Define sy_if 0
# Define sy_then 1
# Define sy_else 2
# Define sy_while 3
# Define sy_begin 4
# Define sy_do 5
# Define sy_end 6
# Define a 7
# Define semicolon 8
# Define e 9
# Define jinghao 10
# Define s 11
# Define L 12

# Define tempsy 15
# Define EA 18/* E end */
# Define EO 19/* E or */

# Define plus 34
# Define times 36
# Define becomes 38
# Define op_and 39
# Define op_or 40
# Define op_not 41
# Define ROP 42

# Define lparent 48 // left parenthesis
# Define rparent 49 // parentheses
# Define ident 56 // variable
# Define intconst 57

Char CH = '/0';/* store read current character */
Int COUNT = 0; // Number of buffer results for lexical analysis
Int count1 = 0;
Static char Spelling [10] = {""};/* store recognized words */
Static char line [81] = {""};/* read a line of characters to the buffer */
Char * pline;/* character buffer pointer */

/* Struct Array {
Int sy11;
Int pos11;
} A [100] cunfangcifajieguo */

Static char ntab1 [100] [10];/* store the variable table */

Struct rwords {
Char SP [10];
Int Sy ;};/* store reserved words. SP indicates reserved words, and SY indicates reserved words */

Struct rwords reswords [10] = {"if", sy_if },
{"Do", sy_do },
{"Else", sy_else },
{"While", sy_while },
{"Then", sy_then },
{"Begin", sy_begin },
{"End", sy_end },
{"And", op_and },
{"Or", op_or },
{"Not", op_not }};

Struct AA {int sy1; // type
Int Pos;/* Internal code value */
} Buf [1000];/* buffer source code for lexical analysis results */

Int nlength = 0;/* record the length of the variable table */

Int lnum = 0;/* source program length */

Int TT1 = 0;/* start position of the variable table */
File * cfile;
File * mfile;

/* Read a row from the file to the buffer */
Void Readline ()
{
Char success;
Pline = line;
Cursor = getchar (cfile); // windows
// Outputs = fgetc (cfile); // Linux
While (Bytes! = '/N ')
{* Pline = Beijing;
Pline ++;
Cursor = getchar (cfile); // windows
// Outputs = fgetc (cfile); // Linux
}
* Pline = '/0 ';
Pline = line;
}/* Read a line in the buffer */

/* Read a character from the buffer zone */
Void readch ()
{If (CH = '/0 ')
{Readline ();
Lnum ++;
}
Ch = * pline;
Pline ++;
}/* Read a char from buffer */

/* Identify (identifier) whether the string has been included in the variable table: if it does not exist, return-1 and vice versa */
Int find (char spel [])
{
Int SS1 = 0;
Int II = 0;
While (SS1 = 0) & (ii <nlength ))
{If (! Strcmp (spel, ntab1 [II])
SS1 = 1;
II ++; // sequential execution
}
If (SS1 = 1) return II-1;
Else return-1;
}

// Identify the identifier
Void identifier ()
{Int IIi = 0, J, K;
Int Ss = 0;
K = 0;
Do // only lowercase letters and numbers are recognized
{Spelling [k] = CH;
K ++;
Readch ();
} While (CH> = 'A') & (CH <= 'Z') | (CH> = '0 ') & (CH <= '9 ')));
Pline --; // rollback
Spelling [k] = '/0'; // Since K in do while has added a 1, the end character'/0' is used here.
While (Ss = 0) & (III <10) // confirm whether it is in reserved words (Search)
{If (! Strcmp (spelling, reswords [III]. SP) // returns 0 if strcmp is equal to or less
Ss = 1; // If the reserved word can be found, the SS value is changed to 1 and the loop exists.
III ++;
}
/* Guanjianzipipei */
If (Ss = 1) // if it is a reserved word
{Buf [count]. sy1 = reswords [III-1]. Sy; // place reserved words in the analysis result Buffer
}
Else
{Buf [count]. sy1 = ident; // identifier type
J = find (spelling );
If (j =-1) // if it does not exist
{Buf [count]. Pos = TT1; // here, the variable position in the variable table is used to mark the internal code value.
Strcpy (ntab1 [TT1], spelling); // copy
TT1 ++; // position 1
Nlength ++; // The length of the variable table plus one
}
Else Buf [count]. Pos = J; // if such a variable already exists, the incode value is the position of the first variable
}
Count ++; // The number of lexical analysis buffer results plus one
For (k = 0; k <10; k ++) Spelling [k] = ''; // clear
}/* Shuzideshibie */
/*
Void number () // recognition constant
{Int ivalue = 0;
Int digit;
// Convert characters to numbers
Do
{Digit = CH-'0'; // the size of [0-9]
Ivalue = ivalue * 10 + digit; // Constant Value
Readch (); // read the next character
} While (CH> = '0') & (CH <= '9 '));
Buf [count]. sy1 = intconst; // constant type
Buf [count]. Pos = ivalue; // Constant Value
Count ++;
Pline --; // rollback
}
*/

Void number ()
{Float invalue = 0.0, Index = 0.0, digit = 0.0;
Int flag = 0;
Do
{
If (CH = '.') & (flag = 0 ))
{
Flag ++;
Readch ();
Continue;
}
If (CH> = '0') & (CH <= '9 '))
{
If (FLAG)
{
Index = Index * 0.1;
Digit = CH-'0 ';
Invalue = invalue + digit * index;
}
Else
{
Digit = CH-'0 ';
Invalue = invalue * 10 + digit;
}
}
Readch ();
} While (CH> = '0') & (CH <= '9') | (CH = '.'));
Buf [count]. sy1 = intconst;
Buf [count]. Pos = invalue;
Count ++;
Pline --;
}

// Scan the main function
Void scan ()
{
While (Ch! = '~ ')
{Switch (CH)
{Case '': break;
Case 'A ':
Case 'B ':
Case 'C ':
Case 'D ':
Case 'E ':
Case 'F ':
Case 'G ':
Case 'H ':
Case 'I ':
Case 'J ':
Case 'K ':
Case 'l ':
Case 'M ':
Case 'N ':
Case 'O ':
Case 'p ':
Case 'q ':
Case 'r ':
Case's ':
Case 'T ':
Case 'U ':
Case 'V ':
Case 'W ':
Case 'X ':
Case 'y ':
Case 'Z ':
Identifier ();
Break;
Case '0 ':
Case '1 ':
Case '2 ':
Case '3 ':
Case '4 ':
Case '5 ':
Case '6 ':
Case '7 ':
Case '8 ':
Case '9 ':
Number ();
Break;
Case '<':
Readch ();
If (CH = ')
Buf [count]. Pos = 0;
Else
{If (CH = '>') BUF [count]. Pos = 4;
Else
{Buf [count]. Pos = 1;
Pline --;
}
}
Buf [count]. sy1 = ROP;
Count ++;
Break;
Case '> ':
Readch ();
If (CH = ')
{Buf [count]. Pos = 2;
}
Else
{Buf [count]. Pos = 3;
Pline --;
}
Buf [count]. sy1 = ROP;
Count ++;
Break;
Case '(':
Buf [count]. sy1 = lparent;
Count ++;
Break;
Case ')':
Buf [count]. sy1 = rparent;
Count ++;
Break;
Case '#':
Buf [count]. sy1 = jinghao;
Count ++;
Break;
Case '+ ':
Buf [count]. sy1 = plus;
Count ++;
Break;
Case '*':
Buf [count]. sy1 = times;
Count ++;
Break;
Case ':':
Readch ();
If (CH = ')
Buf [count]. sy1 = becomes;
Count ++;
Break;
Case '= ':
Buf [count]. sy1 = ROP;
Buf [count]. Pos = 5;
Count ++;
Break;
Case ';':
Buf [count]. sy1 = semicolon;
Count ++;
Break;
}
Readch ();
}
Buf [count]. sy1 =-1;
Buf [count]. Pos =-1;
}

Void disp1 ()
{Int temp1 = 0;
Printf ("/n ********** cifafenxijieguo ***********/N ");
For (temp1 = 0; temp1 <= count; temp1 ++)
{
Printf ("% d/T % d/N", Buf [temp1]. sy1, Buf [temp1]. Pos );
If (temp1 = 20)
{Printf ("press any key to continue.../N ");
Getchar ();
}
}
Getchar ();
}

Void disp4 ()

{Int temp1 = 0;
Mfile = fopen ("cf.txt", "W ");
Printf ("/n ******* zidongshenchengwenjian ******/N ");
For (temp1 = 0; temp1 <count; temp1 ++)
Fprintf (mfile, "% d/T % d/N", Buf [temp1]. sy1, Buf [temp1]. Pos );
Fprintf (mfile ,"~ /N ");
}

Void disp3 ()
{
Int tttt;
Mfile = fopen ("bl.txt", "W ");
Printf ("/n % d, % d/N", lnum, count );
Getchar ();
Printf ("/n ********** bianliaangbiao ***********/N ");
For (tttt = 0; tttt <TT1; tttt ++)
{Printf ("% d/T % s/n", tttt, ntab1 [tttt]);
Fprintf (mfile, "% d/T % s/n", tttt, ntab1 [tttt]);
}
Fprintf (mfile ,"~ /N ");
Getchar ();
}

Int main ()
{
If (cfile = fopen ("2.txt"," R "))! = NULL)
Printf ("Open/N ");
Else
Printf ("close/N ");
Readch ();
Printf ("% C/N", CH );
Scan ();
Disp1 ();
Disp4 ();
Disp3 ();
Return 0;
}