what would I use to count number of words

This is a discussion on what would I use to count number of words within the C Programming forums, part of the General Programming Boards category; quick question, I have a string Code: int main ( ) { char string [ 25 ] = "Hello My ...

  1. #1
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    what would I use to count number of words

    quick question, I have a string

    Code:
    int main ( )
    {
    char string [ 25 ] = "Hello My  Name  is   Ben";
    
    }
    How would I count the number of words in the string? I tried counting the number of spaces but if they put more than one space between each word It would throw me off.

    Thanks in advance.

  2. #2
    Deathray Engineer MacGyver's Avatar
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    How would you do it yourself?

    Count spaces, but ignore all spaces preceeded by a space.

  3. #3
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    how in the heck would you ignore spaces after a space?

  4. #4
    Deathray Engineer MacGyver's Avatar
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    Here's some pseudo-pseudocode:

    Code:
    lastchar = '\0'
    Loop for length of string
    	if currentchar = ' ' AND lastchar != ' '
    		count++;
    	lastchar = currentchar
    Edit: Oh, and you probably want to add one to count when you're done. But even then, this is making some assumptions about the string it'll be analyzing.
    Last edited by MacGyver; 04-27-2007 at 12:48 PM.

  5. #5
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    Isnt there a way to break up a string into tokens?

  6. #6
    C++ Witch laserlight's Avatar
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    Yes, with strtok().
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  7. #7
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    and you use strtok how?

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    Think of the problem in terms of state machines. For simplicity I'll describe a Moore type state machine that would do the trick. (A Mealy type would be more efficient and I recommend you convert this to Mealy.) In each state there will be an action that is performed (e.g. increment the word count) and a set of conditions that dictate transitions to new states.

    Here are some proposed states:

    StartWord: (Occurs when we first detect a word)
    Action: increment word counter
    whitespace: go to White state
    ascii: if not white go to Word state

    White: (Occurs when we are processing white characters (e.g. space, tab newline etc.))
    Action: none
    whitespace: go to White state
    ascii: go to StartWord

    Word: You can figure this out yourself.


    C implementation. The standard and inefficent approach will be to implement this using the switch statement. The state values would be determined via #define statements

    switch(state) {
    case StartWord:
    wordcount++ ;
    if ((c == ' ') || (c == '/t') || (c == '\n')) {
    state = White ;
    } else {
    state = Word ;
    }
    break
    case White:
    ....
    break ;
    case Word:
    ...
    break ;
    }
    The superior approach is to use the dreaded goto statement to handle the state transitions. c would contain the current character and the whole mess would be wrapped in a while loop, whilst reading one character at a time from the input stream (e.g. using getchar() or scanf etc.). Although goto is strongly discouraged in structured programming, it makes perfect sense for a state machine and really is not any harder to read than a switch statement for this purpose. It's when go tos jump out of loops that things get messy.

  9. #9
    C++ Witch laserlight's Avatar
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    hmm... have you not tried to search?
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  10. #10
    Registered User Noir's Avatar
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    Although goto is strongly discouraged in structured programming, it makes perfect sense for a state machine and really is not any harder to read than a switch statement for this purpose.
    I don't believe that. Can you prove it?

  11. #11
    Captain Crash brewbuck's Avatar
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    Quote Originally Posted by SevenThunders View Post
    The superior approach is to use the dreaded goto statement to handle the state transitions. c would contain the current character and the whole mess would be wrapped in a while loop, whilst reading one character at a time from the input stream (e.g. using getchar() or scanf etc.). Although goto is strongly discouraged in structured programming, it makes perfect sense for a state machine and really is not any harder to read than a switch statement for this purpose. It's when go tos jump out of loops that things get messy.
    You don't need goto...

    Code:
    #include <ctype.h>
    
    #define IN_WORD 0
    #define IN_SPACE 1
    
    int count_words(const char *str)
    {
        int nwords = 0;
        int state;
    
        if(!*str) return 0;
        if(isspace(*str)) state = IN_SPACE;
        else
        {
            state = IN_WORD;
            nwords = 1;
        }
        while(*++str)
        {
            switch(state)
            {
            case IN_SPACE:
                if(!isspace(*str))
                {
                    state = IN_WORD;
                    nwords++;
                }
                break;
            case IN_WORD:
                if(isspace(*str)) state = IN_SPACE;
                break;
            }
        }
        return nwords;
    }

  12. #12
    Captain Crash brewbuck's Avatar
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    Quote Originally Posted by MacGyver View Post
    How would you do it yourself?

    Count spaces, but ignore all spaces preceeded by a space.
    Wouldn't work. Take the simple rule of counting the spaces and then adding one. There is one space in "Two Words," 1+1 = 2, so there are 2 words. It's simple to add the rule "except when a space is preceded by another space." But if the input string is two spaces and nothing else, there is one space which is not preceded by a space, so there is 1 counted space. Add 1 to this according to the aforementioned rule, and you get the result that a string consisting only of 2 or more spaces contains 2 words.

  13. #13
    Captain Crash brewbuck's Avatar
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    Here's a recursive example. I don't actually recommend using it (it's a silly waste of stack space for this kind of problem), but it shows how recursion can make things much easier at least in principle:

    Code:
    int count_words(const char *str)
    {
        return count_words_r(str, ' ');
    }
    
    /* Recursive worker function */
    int count_words_r(const char *str, char last)
    {
       if(!*str) return 0;
       return count_words_r(str + 1, *str) + ((!isspace(*str) && isspace(last)) ? 1 : 0);
    }
    Last edited by brewbuck; 04-27-2007 at 01:52 PM.

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    My program should at the moment read from a file called input, create two new files called east and west. And then print Roster number x for each player. Right now I am working on how to break up each word in the input file into tokens. and print them off in this order.

    Roster# Lastname, Firstname, Hometeam, Scoring average

    my input file is

    Code:
    Joseph Stevens Boys 11 20 5
    Jamie Stevens Girls 22 18 6
    Tony Waters Boys 33 22 7
    Sally Smith Girls 44 33 8
    My program is:

    Code:
    int main ( void )
    {
    char str [ 80 ];
    char first;
    char last;
    char *token;
    int points;
    int games;
    int number;
    int x;
    int roster;
    int y;
    int a = 0;
    FILE * input, * east, * west;
    char array [ 81 ];
    char string [ 80 ] = "Hello My Name is Ben";
    
    if ( ( input = fopen ( "input", "r" ) ) == NULL )
    {
            printf ( "Cannot open file\n" );
            exit ( 1 );
    }
    
    if ( ( east = fopen ( "east", "w" ) ) == NULL )
    {
            printf ( "Cannot open file\n" );
            exit ( 1 );
    }
    
    if ( ( west = fopen ( "west", "w" ) ) == NULL )
    {
            printf ( "Cannot open file\n" );
            exit ( 1 );
    }
    
    "mylab8.c" 73 lines, 1259 characters
    }
    
    x = -1;
    while ( ! feof ( input ) )
            {
            fgets (str, 80, input );
            x ++;
            }
    y = x + 1;
    for (roster = 1; roster < y; roster ++)
            {
            fprintf (east, "Roster# is %d\n", roster);
            fprintf (west, "Roster# is %d\n", roster);
            }
    fgets (str, 80, input );
    
    stringtoken ( str );
    
    }
    
    
    int stringtoken ( char string )
    
    {
    char *token;
    
       printf( "Tokens:\n" );
       /* Establish string and get the first token: */
       token = strtok( string, " ,\n\t" );
       while( token != NULL )
       {
          /* While there are tokens in "string" */
          printf( " %s\n", token );
          /* Get next token: */
          token = strtok( NULL, " ,\n\t" );
       }
    }
    And my error when I try to compile is

    mylab8.c:60: warning: type mismatch with previous implicit declaration
    mylab8.c:53: warning: previous implicit declaration of `stringtoken'
    mylab8.c: In function `stringtoken':
    mylab8.c:65: warning: assignment makes pointer from integer without a cast
    mylab8.c:71: warning: assignment makes pointer from integer without a cast

  15. #15
    Captain Crash brewbuck's Avatar
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    Quote Originally Posted by s_jsstevens View Post
    My program should at the moment read from a file called input, create two new files called east and west. And then print Roster number x for each player. Right now I am working on how to break up each word in the input file into tokens. and print them off in this order.
    Why are you posting this here?

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