Counting words in a string - c programming

Question

I need to write a function that will count words in a string. For the purpose of this assignment, a "word" is defined to be a sequence of non-null, non-whitespace characters, separated from other words by whitespace.

This is what I have so far:

int words(const char sentence[ ]);

int i, length=0, count=0, last=0;
length= strlen(sentence);

for (i=0, i<length, i++)
 if (sentence[i] != ' ')
     if (last=0)
        count++;
     else
        last=1;
 else
     last=0;

return count;

I am not sure if it works or not because I can't test it until my whole program is finished and I am not sure it will work, is there a better way of writing this function?

Solution 1

You needed

int words(const char sentence[])
{
}

(note braces).

For loops go with ; instead of ,.

---

Without any disclaimer, here's what I'd have written:

See it live http://ideone.com/uNgPL

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

int words(const char sentence[ ])
{
    int counted = 0; // result

    // state:
    const char* it = sentence;
    int inword = 0;

    do switch(*it) {
        case '\0': 
        case ' ': case '\t': case '\n': case '\r': // TODO others?
            if (inword) { inword = 0; counted++; }
            break;
        default: inword = 1;
    } while(*it++);

    return counted;
}

int main(int argc, const char *argv[])
{
    printf("%d\n", words(""));
    printf("%d\n", words("\t"));
    printf("%d\n", words("   a      castle     "));
    printf("%d\n", words("my world is a castle"));
}

Solution 2

See the following example, you can follow the approach : count the whitespace between words .

int words(const char *sentence)
{
    int count=0,i,len;
    char lastC;
    len=strlen(sentence);
    if(len > 0)
    {
        lastC = sentence[0];
    }
    for(i=0; i<=len; i++)
    {
        if((sentence[i]==' ' || sentence[i]=='\0') && lastC != ' ')
        {
            count++;
        }
        lastC = sentence[i];
    }
    return count;
}

To test :

int main() 
{ 
    char str[30] = "a posse ad esse";
    printf("Words = %i\n", words(str));
}

Output :

Words = 4

Solution 3

#include <ctype.h> // isspace()

int
nwords(const char *s) {
  if (!s) return -1;

  int n = 0;
  int inword = 0;
  for ( ; *s; ++s) {
    if (!isspace(*s)) {
      if (inword == 0) { // begin word
        inword = 1;
        ++n;
      }
    }
    else if (inword) { // end word
      inword = 0;
    }
  }
  return n;
}

Solution 4

bool isWhiteSpace( char c )
{
    if( c == ' ' || c == '\t' || c == '\n' )
        return true;
    return false;
}

int wordCount( char *string )
{
    char *s = string;
    bool inWord = false;
    int i = 0;

    while( *s )
    {
        if( isWhiteSpace(*s))
        {
            inWord = false;
            while( isWhiteSpace(*s) )
                s++;
        }
        else
        {
            if( !inWord )
            {
                inWord = true;
                i++;
            }
            s++;
        }
    }

    return i;
}

Solution 5

Here is one of the solutions. It counts words with multiple spaces or just space or space followed by the word.

#include <stdio.h>
int main()
{
    char str[80];
    int i, w = 0;
    printf("Enter a string: ");
    scanf("%[^\n]",str);

    for (i = 0; str[i] != '\0'; i++)
    {
       
        if((str[i]!=' ' && str[i+1]==' ')||(str[i+1]=='\0' && str[i]!=' '))
        {
            w++;
        }
        
    }

    printf("The number of words = %d", w );

    return 0;
}

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