Count words in a user-input string in C

Question

So, we were given this program in class. "Write a Program in C to count the number of words in a sentence input by the user." This is what i could come up with, but the number of words is always one less than what is the correct number. My teacher told everyone to just add 1 to the word count before printing it. I think it has a bug, if we don't enter any words, i.e. , press Enter instead of typing,the program suggested by my teacher would still give word count as 1 not 0. Do you know of any way to get proper word count without just adding 1 at the end? Code:

My code(giving 1 less than correct) :

#include <stdio.h>
#include <string.h>
void main()
{
 char s[200];
 int count = 0, i;
 printf("enter the string\n");
 gets(s);
 for (i = 0;i<strlen(s);i++)
 {
  if (s[i] == ' ')
  count++;    
 }
 printf("number of words in given string are: %d\n", count);
}

Solution 1

It's just that you're counting spaces, this would also be incorrect if the user ended the string with a bunch of spaces. Try something like this:

#include <stdio.h>
#include <string.h>
void main()
{
 char s[200];
 int count = 0, i;
 int foundLetter = False;
 printf("enter the string\n");
 gets(s);
 for (i = 0;i<strlen(s);i++)
 {
  if (s[i] == ' ')
      foundLetter = False;
  else 
  {    
      if (foundLetter == False)
          count++;
      foundLetter = True;
  }
 }
 printf("number of words in given string are: %d\n", count);
}

As other users have commented, your program is susceptible to many other issues depending on the string inputed. The example I have posted assumes that anything that is not a space is a letter and if you find at least one letter, than that's a word. Instead of boolean values you could use a counter to make sure that the word is at least a certain length. You could also check to see that it is not a number or symbol by either writing your own regex function or using an existing one. As others have said there is a lot more you can do with this program, but I've provided an example to point you in the right direction.

Solution 2

You are counting the amount of non-words, but you should be counting the amount of words.

If a word is defined as a sequence of one or more letters, your code might go as:

for every character in the string
  if the character is part of a word ( "the car's wheel" is three words )
    increase the word count
    while the character is part of a word, increment your pointer