final.c

c写的一个c小段程序编译程序

#include <stdio.h>
#include <ctype.h>
#include <string.h>

 
#define ID 1
#define INT 2
#define KEY 3
#define LT  4
#define LE  5
#define GE  6
#define GT  7
#define EQ  8
#define LB  9
#define RB  10
#define LBB 11
#define RBB 12
#define ADD 13
#define SUB 14
#define MUL 15
#define DIV 16
#define SEM 17
#define ASS 18
#define ERROR 0

char * key[16] =
{
  "int", "main", "while", "char", "long", "short", "float", "struct", "union", "while", "if", "printf",
       "scanf", "for", "else", "switch"
};



int lookupid( char * p, char * q[], int r );
char * lookupkey( char * p, char * q[16] );
void output( int i, char * p );
int switchnumber(char *p[],int i);
int calculate(int a,int b,char *p[]);






char * gettoken( int Method ,char * p[] );
int numbercheck( char * p[] );
int opcheck( char * p[] );
int idcheck( char * t[],int r, char * q );
void definition( char * t[],int r,char * p[] );
void assignment( char * t[],int r,char * p[] );
void condition( char * t[], int r,char * p[] );
void procedure( char * t[],int r,char * p[] );
void syntaxanalyse( char * t[],int r,char * p[] );

void report_error( void )
{
  printf( "input a illegal charactor!\n" );
}






main()
{
  FILE * fp, * fp1;
  char ch, c[16], token[20];
  char space[] ={' '}, space1[] = "     ";
  int i, a,b, j = 1, r = 1;
  long int w;
  char * tokentable[50], * idtable[10];
  idtable[1] = space1;

  printf("reading characters from 'a.c'......\n\n");
  for (w=1;w<=100000000;w++)
  { ;
   }
  fp = fopen( "a.c", "r" );


  while ( !feof( fp ) )
  {
    ch = fgetc( fp );
    if ( isalpha( ch ) )
    {
      token[0] = ch;
      ch = fgetc( fp );
      i = 1;
      while ( isalnum( ch ) )
      {
        token[i] = ch;
        i++;
        ch = fgetc( fp );
      }
      token[i] = '\0';
      tokentable[j] = strdup( token );
      j++;
      fseek( fp, -1, 1 );
      /* backward a byte */

      strcpy( c, lookupkey( token, key ) );
      if ( strcmp( c, "0" ) == 0 )
      {
        output( ID, token );
        if ( r == 1 )
          {idtable[r] = strdup( token );
          r++;}
        else
        {
          w = lookupid( token, idtable, r - 1 );
          if ( w == 0 )
          {
          idtable[r] = strdup( token );
          r++;
          }
        }

      }
     else
        output( KEY, c );
    }
    /* identifier or key testing */

    else if ( isdigit( ch ) )
    {
      token[0] = ch;
      ch = fgetc( fp );
      i = 1;
      while ( isdigit( ch ) )
      {
        token[i] = ch;
        i++;
        ch = fgetc( fp );
      }
      token[i] = '\0';
      tokentable[j] = strdup( token );
      j++;
      fseek( fp, -1, 1 );

      output( INT, token );
    }
    /* digit testing */


    else
    {
      if ( ch > '!' && ch < '~' )
        switch ( ch )
        {
          case '<':
            ch = fgetc( fp );
            if ( ch == '=' )
            {
              strcpy( token, "<=" );
              tokentable[j] = strdup( token );
              j++;
              output( LE, space );
            }
            else
            {
              fseek( fp, -1, 1 );
              strcpy( token, "<" );
              tokentable[j] = strdup( token );
              j++;
              output( LT, space );
            }
          break;
          case '>':
            ch = fgetc( fp );
            if ( ch == '=' )
            {
              strcpy( token, ">=" );
              tokentable[j] = strdup( token );
              j++;
              output( GE, space );
            }
            else
            {
              fseek( fp, -1, 1 );
              strcpy( token, ">" );
              tokentable[j] = strdup( token );
              j++;
              output( GT, space );
            }
          break;
          case '=':
             ch = fgetc( fp );
             if ( ch == '=' )
            {
              output( EQ, space );
              strcpy( token, "==" );
              tokentable[j] = strdup( token );
              j++;
            }
            else
            {
              fseek( fp, -1, 1 );
              strcpy( token, "=" );
              tokentable[j] = strdup( token );
              j++;
              output( ASS, space );
            }
          break;
          case '(':
            {
              output( LB, space );
              strcpy( token, "(" );
              tokentable[j] = strdup( token );
              j++;
            }
          break;
          case ')':
            {
              output( RB, space );
              strcpy( token, ")" );
              tokentable[j] = strdup( token );
              j++;
            }
          break;
          case '{':
            {
              output( LBB, space );
              strcpy( token, "{" );
              tokentable[j] = strdup( token );
              j++;
            }
          break;
          case '}':
            {
              output( RBB, space );
              strcpy( token, "}" );
              tokentable[j] = strdup( token );
              j++;
            }
          break;
          case '+':
            {
              output( ADD, space );
              strcpy( token, "+" );
              tokentable[j] = strdup( token );
              j++;

            }
          break;
          case '-':
            {
              output( SUB, space );
              strcpy( token, "-" );
              tokentable[j] = strdup( token );
              j++;
            }
          break;
          case '*':
            {
              output( MUL, space );
              strcpy( token, "*" );
              tokentable[j] = strdup( token );
              j++;
            }
          break;
          case '/':
            {
              output( DIV, space );
              strcpy( token, "/" );
              tokentable[j] = strdup( token );
              j++;
            }
          break;
          case ';':
            {
              output( SEM, space );
              strcpy( token, ";" );
              tokentable[j] = strdup( token );
              j++;
            }
          break;
          default:
            report_error();
          break;
        }
      /* switch */
    }
    /* else */
  }
  /* while */

  fclose( fp );

  fp1 = fopen( "b.c", "a" );

   fprintf( fp1, "\n\n\n List of tokentable:\n");
  for ( w = 1; w <= ( j - 1 ); w++ )

    fprintf( fp1, "%s\n", tokentable[w] );

  fprintf( fp1, "\n\n\n List of idtable:\n");
  for ( w = 1; w <= ( r - 1 ); w++ )

    fprintf( fp1, "%s\n", idtable[w] );


  printf("Accidence analysis completed! you can check it up in the file 'b.c'...\n\n");
  fclose( fp1 );
  printf("U want to continue to begin syntax analysis?\npress Enter to continue...\n");
  ch=getchar();
  if(ch=='\n')
     {
      printf("Syntax analysing......\n");
     for(w=1;w<=100000000;w++)
       { ;
       }
     syntaxanalyse( idtable,r-1,tokentable );
     }

  printf("\n\nU can modify your program with the hints above,\nif there is no error, press Enter to continue...\n");
  ch=getchar();
  if(ch=='\n')
  {
        a=switchnumber(tokentable,16);
        b=switchnumber(tokentable,20);
        if(b==0&&strcmp(tokentable[31],"/")==0)
          printf("Error,the divisor can not be 0!");
        else

        {
        if(strcmp(tokentable[25],">")==0)
         {
         if(a>b)
           {
           w=calculate(a,b,tokentable);
           printf("The result is %d.",w);
           }
         else printf("The condition was not satisfied,no result.");
         }
        else if(strcmp(tokentable[25],"<")==0)
         {
         if(a<b)
          {
          w=calculate(a,b,tokentable);
          printf("The result is %d.",w);
          }
         else printf("The condition was not satisfied,no result.");
         }
       else if(strcmp(tokentable[25],"==")==0)
         {
         if(a==b)
           {
           w=calculate(a,b,tokentable);
           printf("The result is %d.",w);
           }
         else printf("The condition was not satisfied,no result.");
         }
       else if(strcmp(tokentable[25],"<=")==0)
         {
         if(a<=b)
           {
           w=calculate(a,b,tokentable);
           printf("The result is %d.",w);
           }
         else printf("The condition was not satisfied,no result.");
         }
      else
         {
         if(a>=b)
           {
           w=calculate(a,b,tokentable);
           printf("The result is %d.",w);
           }
         else printf("The condition was not satisfied,no result.");
         }
      }/*else*/
    } /*if*/

getch();
}

/* 词法分析部分 */


/* 下面做语法分析 */