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Faulty C Program - find where the fault is?

Discussion in 'Programming' started by Venny, Jan 26, 2011.

  1. Venny

    Venny New Member

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    Hi All,

    I am working on this faulty C program but not able to figure out what the actual fault is :( Please help !
    Code:
     
    #include <stdio.h>
    #include <ctype.h>
    #include <string.h>
    #include "tokens.h"
    #define TRUE 1
    #define FALSE 0
    
    main(argc,argv)
    int argc;
    char *argv[3];
    { char *fname;
    token tok;
    token_stream tp;
    if(argc==1) /* if not given filename,take as '""' */
    {
    fname= (char *) malloc(sizeof(char));
    *fname = '\0';
    }
    else if(argc==2)
    fname= argv[1];
    else
    { fprintf(stdout, "Error!,please give the token stream\n");
    exit(0);
    }
    tp=open_token_stream(fname); /* open token stream */
    tok=get_token(tp);
    while (is_eof_token(tok) ==FALSE) /* take one token each time until eof */
    {
    print_token(tok);
    tok=get_token(tp);
    }
    print_token(tok); /* print eof signal */
    exit(0);
    }
    
     
    character_stream open_character_stream(fname)
    char *fname;
    { character_stream fp;
    if(fname == NULL)
    fp=stdin;
    else if ((fp=fopen(fname,"r"))== NULL)
    {
    fprintf(stdout, "The file %s doesn't exists\n",fname);
    exit(0);
    }
    return(fp);
    }
    
     
    char get_char(fp)
    character_stream fp;
    { char ch;
    ch=getc(fp);
    return(ch);
    }
    
     
    char unget_char(ch,fp)
    character_stream fp;
    char ch;
    { char c;
    c=ungetc(ch,fp);
    if(c ==EOF)
    {
    return(c);
    }
    else
    return(c);
    }
    
     
    
     
    char buffer[81]; /* fixed array length MONI */ /* to store the token temporar */
    
     
    static int is_spec_symbol();
    static int is_token_end();
    static unget_error();
    static int is_keyword();
    static int is_identifier();
    static int is_num_constant();
    static int is_char_constant();
    static int is_str_constant();
    static int is_comment();
    static void print_spec_symbol();
    
     
    token_stream open_token_stream(fname)
    char *fname;
    {
    token_stream fp;
    if(strcmp(fname,"")==0)
    fp=open_character_stream(NULL);
    else
    fp=open_character_stream(fname);
    return(fp);
    }
    
    /********************************************************/
    /* NAME : get_token */
    /* INPUT: a pointer to the tokens_stream */
    /* OUTPUT: a token */
    /* DESCRIPTION: according the syntax of tokens,dealing */
    /* with different case and get one token */
    /********************************************************/
    token get_token(tp)
    token_stream tp;
    { 
    int i=0,j;
    int id=0;
    char ch,ch1[2];
    for (j=0;j<=80;j++) /* initial the buffer */
    { buffer[j]='\0';} 
    ch1[0]='\0';
    ch1[1]='\0';
    ch=get_char(tp);
    while(ch==' '||ch=='\n') /* strip all blanks until meet characters */
    {
    ch=get_char(tp);
    } 
    buffer[i]=ch;
    if(is_eof_token(buffer)==TRUE)return(buffer);
    if(is_spec_symbol(buffer)==TRUE)return(buffer); 
    if(ch =='"')id=1; /* prepare for string */
    if(ch ==59)id=0; /* prepare for comment */
    ch=get_char(tp);
    
    while (is_token_end(id,ch) == FALSE)/* until meet the end character */
    {
    i++;
    buffer[i]=ch;
    ch=get_char(tp);
    }
    ch1[0]=ch; /* hold the end charcater */
    if(is_eof_token(ch1)==TRUE) /* if end character is eof token */
    { ch=unget_char(ch,tp); /* then put back eof on token_stream */
    if(ch==EOF)unget_error(tp);
    return(buffer);
    }
    if(is_spec_symbol(ch1)==TRUE) /* if end character is special_symbol */
    { ch=unget_char(ch,tp); /* then put back this character */
    if(ch==EOF)unget_error(tp);
    return(buffer);
    }
    if(id==1) /* if end character is " and is string */
    { i++; /* case,hold the second " in buffer */
    buffer[i]=ch;
    return(buffer); 
    }
    if(id==0 && ch==59)
    /* when not in string or comment,meet ";" */
    { ch=unget_char(ch,tp); /* then put back this character */
    if(ch==EOF)unget_error(tp);
    return(buffer); 
    }
    return(buffer); /* return nomal case token */
    }
    
    /*******************************************************/
    /* NAME: is_token_end */
    /* INPUT: a character,a token status */
    /* OUTPUT: a BOOLEAN value */
    /*******************************************************/
    static int is_token_end(str_com_id,ch)
    char ch;
    int str_com_id;
    { char ch1[2]; /* fixed array declaration MONI */
    ch1[0]=ch;
    ch1[1]='\0';
    if(is_eof_token(ch1)==TRUE)return(TRUE); /* is eof token? */
    if(str_com_id==1) /* is string token */
    { if(ch=='"' | ch=='\n') /* for string until meet another " */
    return(TRUE);
    else
    return(FALSE);
    }
    
    if(str_com_id==2) /* is comment token */
    { if(ch=='\n') /* for comment until meet end of line */
    return(TRUE);
    else
    return(FALSE);
    }
    
    if(is_spec_symbol(ch1)==TRUE) return(TRUE); /* is special_symbol? */
    if(ch ==' ' || ch=='\n' || ch==59) return(TRUE); 
    /* others until meet blank or tab or 59 */
    return(FALSE); /* other case,return FALSE */
    }
    
    /****************************************************/
    /* NAME : token_type */
    /* INPUT: a pointer to the token */
    /* OUTPUT: an integer value */
    /* DESCRIPTION: the integer value is corresponding */
    /* to the different token type */
    /****************************************************/
    static int token_type(tok)
    token tok;
    { 
    if(is_keyword(tok))return(keyword);
    if(is_spec_symbol(tok))return(spec_symbol);
    if(is_identifier(tok))return(identifier);
    if(is_num_constant(tok))return(num_constant);
    if(is_str_constant(tok))return(str_constant);
    if(is_char_constant(tok))return(char_constant);
    if(is_comment(tok))return(comment);
    if(is_eof_token(tok))return(end);
    return(error); /* else look as error token */
    }
    
    /****************************************************/
    /* NAME: print_token */
    /* INPUT: a pointer to the token */
    /* OUTPUT: a BOOLEAN value,print out the token */
    /* according the forms required */
    /****************************************************/
    int print_token(tok)
    token tok;
    { int type;
    type=token_type(tok);
    if(type==error)
    { fprintf(stdout, "error,\"%s\".\n",tok);
    } 
    if(type==keyword)
    {fprintf(stdout, "keyword,\"%s\".\n",tok);
    }
    if(type==spec_symbol)print_spec_symbol(tok);
    if(type==identifier)
    {fprintf(stdout, "identifier,\"%s\".\n",tok);
    }
    if(type==num_constant)
    {fprintf(stdout, "numeric,%s.\n",tok);
    }
    if(type==str_constant)
    {fprintf(stdout, "string,%s.\n",tok);
    }
    if(type==char_constant)
    {tok=tok+1;
    fprintf(stdout, "character,\"%s\".\n",tok);
    }
    if(type==end) 
    fprintf(stdout, "eof.\n");
    }
    
    /* the code for tokens judgment function */
    
    /*************************************/
    /* NAME: is_eof_token */
    /* INPUT: a pointer to a token */
    /* OUTPUT: a BOOLEAN value */
    /*************************************/
    int is_eof_token(tok)
    token tok;
    { 
    if( *tok==EOF)
    return(TRUE);
    else
    return(FALSE);
    }
    
    /*************************************/
    /* NAME: is_comment */
    /* INPUT: a pointer to a token */
    /* OUTPUT: a BOOLEAN value */
    /*************************************/
    static int is_comment(ident)
    token ident;
    {
    if( (*ident) ==59 ) /* the char is 59 */
    return(TRUE);
    else
    return(FALSE);
    }
    
    /*************************************/
    /* NAME: is_keyword */
    /* INPUT: a pointer to a token */
    /* OUTPUT: a BOOLEAN value */
    /*************************************/
    static int is_keyword(str)
    token str;
    { 
    if (!strcmp(str,"and") || !strcmp(str,"or") || !strcmp(str,"if") ||
    !strcmp(str,"xor")||!strcmp(str,"lambda")||!strcmp(str,"=>"))
    return(TRUE);
    else 
    return(FALSE);
    }
    
    /*************************************/
    /* NAME: is_char_constant */
    /* INPUT: a pointer to a token */
    /* OUTPUT: a BOOLEAN value */
    /*************************************/
    static int is_char_constant(str)
    token str;
    {
    if ((*str)=='#' && isalpha(*(str+1)))
    return(TRUE);
    else 
    return(FALSE);
    }
    
    /*************************************/
    /* NAME: is_num_constant */
    /* INPUT: a pointer to a token */
    /* OUTPUT: a BOOLEAN value */
    /*************************************/
    static int is_num_constant(str)
    token str;
    {
    int i=1;
    
    if ( isdigit(*str)) 
    {
    while ( *(str+i) != '\0' ) /* until meet token end sign */
    {
    if(isdigit(*(str+i)))
    i++;
    else
    return(FALSE);
    } /* end WHILE */
    return(TRUE);
    }
    else
    return(FALSE); /* other return FALSE */
    }
    
    /*************************************/
    /* NAME: is_str_constant */
    /* INPUT: a pointer to a token */
    /* OUTPUT: a BOOLEAN value */
    /*************************************/
    static int is_str_constant(str)
    token str;
    {
    int i=1;
    
    if ( *str =='"')
    { while (*(str+i)!='\0') /* until meet the token end sign */
    { if(*(str+i)=='"')
    return(TRUE); /* meet the second '"' */
    else
    i++;
    } /* end WHILE */
    return(FALSE);
    }
    else
    return(FALSE); /* other return FALSE */
    }
    /*************************************/
    /* NAME: is_identifier */
    /* INPUT: a pointer to a token */
    /* OUTPUT: a BOOLEAN value */
    /*************************************/
    static int is_identifier(str)
    token str;
    {
    int i=1;
    
    if ( isalpha( *str) ) 
    {
    while( *(str+i) !='\0' ) /* unti meet the end token sign */
    { 
    if(isalpha(*(str+i)) || isdigit(*(str+i))) 
    i++;
    else
    return(FALSE);
    } /* end WHILE */
    return(TRUE);
    }
    else
    return(FALSE);
    }
    
    /******************************************/
    /* NAME: unget_error */
    /* INPUT: a pointer to token stream */
    /* OUTPUT: print error message */
    /******************************************/
    static unget_error(fp)
    character_stream *fp;
    {
    fprintf(stdout,"It can not get charcter\n");
    }
    
    /*************************************************/
    /* NAME: print_spec_symbol */
    /* INPUT: a pointer to a spec_symbol token */
    /* OUTPUT : print out the spec_symbol token */
    /* according to the form required */
    /*************************************************/
    static void print_spec_symbol(str)
    token str;
    {
    if (!strcmp(str,"("))
    {
    fprintf(stdout, "%s\n","lparen.");
    return;
    } 
    if (!strcmp(str,")"))
    {
    fprintf(stdout, "%s\n","rparen.");
    return;
    }
    if (!strcmp(str,"["))
    {
    fprintf(stdout, "%s\n","lsquare.");
    return;
    }
    if (!strcmp(str,"]"))
    {
    fprintf(stdout, "%s\n","rsquare.");
    return;
    }
    if (!strcmp(str,"'"))
    {
    fprintf(stdout, "%s\n","quote.");
    return;
    }
    if (!strcmp(str,"`"))
    {
    fprintf(stdout, "%s\n","bquote.");
    return;
    }
    
    fprintf(stdout, "%s\n","comma.");
    }
    
     
    /*************************************/
    /* NAME: is_spec_symbol */
    /* INPUT: a pointer to a token */
    /* OUTPUT: a BOOLEAN value */
    /*************************************/
    static int is_spec_symbol(str)
    token str;
    {
    if (!strcmp(str,"("))
    { 
    return(TRUE);
    }
    if (!strcmp(str,")"))
    {
    return(TRUE);
    }
    if (!strcmp(str,"["))
    {
    return(TRUE);
    }
    if (!strcmp(str,"]"))
    {
    return(TRUE);
    }
    if (!strcmp(str,"'"))
    {
    return(TRUE);
    }
    if (!strcmp(str,"`"))
    {
    return(TRUE);
    }
    if (!strcmp(str,","))
    {
    return(TRUE);
    }
    return(FALSE); /* others return FALSE */
    }
    


    I know its long enough. any help is appreciated!
     
    Last edited by a moderator: Jan 26, 2011
  2. shabbir

    shabbir Administrator Staff Member

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    From where did you paste this code?
     
  3. Venny

    Venny New Member

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    its one of my assignment questions. the code itseld is so wierd.
     
  4. shabbir

    shabbir Administrator Staff Member

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    But who gave you that code is my question?
     
  5. Venny

    Venny New Member

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    y is something going wrong?
     
  6. shabbir

    shabbir Administrator Staff Member

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    No but the person who has given you the code should be able to do that very easily. Isn't it?
     
  7. Venny

    Venny New Member

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    yeah but the person who gave us this wants us to do it all from scratch.. well i figured out what the progrm is suppose to do... bt am finding it difficult to c what the fault is. do u know after i execute a file in cygwin then how do i come out of it. i mean what ever m writing, its taking it as input,

    do u know a way to stop this ?
     
  8. lionaneesh

    lionaneesh New Member

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    I am trying to figure it out...
    Where is the header file "tokens.h"
    Please provide...
     

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