Why is my wc implementation giving wrong word count? - c

Question

Here is a small code snippet.
while((c = fgetc(fp)) != -1)
{
cCount++; // character count
if(c == '\n') lCount++; // line count
else
{
if(c == ' ' && prevC != ' ') wCount++; // word count
}
prevC = c; // previous character equals current character. Think of it as memory.
}
Now when I run wc with the file containing this above snippet code(as is), I am getting 48 words, but when I use my program on same input data, I am getting 59 words.
How to calculate word count exactly like wc does?

Answer 1

You are treating anything that isn't a space as a valid word. This means that a newline followed by a space is a word, and since your input (which is your code snippet) is indented you get a bunch of extra words.
You should use isspace to check for whitespace instead of comparing the character to ' ':
while((c = fgetc(fp)) != EOF)
{
cCount++;
if (c == '\n')
lCount++;
if (isspace(c) && !isspace(prevC))
wCount++;
prevC = c;
}

Answer 2

There is an example of the function you want in the book: "Brian W Kernighan And Dennis M Ritchie: The Ansi C Programming Language". As the author says: This is a bare-bones version of the UNIX program wc. Altered to count only words is like this:
#include <stdio.h>
#define IN 1 /* inside a word */
#define OUT 0 /* outside a word */
/* nw counts words in input */
main()
{
int c, nw, state;
state = OUT;
nw = 0;
while ((c = getchar()) != EOF) {
if (c == ' ' || c == '\n' || c == '\t')
state = OUT;
else if (state == OUT) {
state = IN;
++nw;
}
}
printf("%d\n", nw);
}

Answer 3

Instead of checking for spaces only you should check for escape sequences like \t \n space and so on.
This will give the correct results.
You can use isspace() from <ctype.h>
Change the line
if(c == ' ' && prevC != ' ') wCount++;
to
if(isspace(c) && !(isspace(prevC)) wCount++;
This would give the correct results.
Don't forget to include <ctype.h>

Answer 4

You can do:
int count()
{
unsigned int cCount = 0, wCount = 0, lCount = 0;
int incr_word_count = 0;
char c;
FILE *fp = fopen ("text", "r");
if (fp == NULL)
{
printf ("Failed to open file\n");
return -1;
}
while((c = fgetc(fp)) != EOF)
{
cCount++; // character count
if(c == '\n') lCount++; // line count
if (c == ' ' || c == '\n' || c == '\t')
incr_word_count = 0;
else if (incr_word_count == 0) {
incr_word_count = 1;
wCount++; // word count
}
}
fclose (fp);
printf ("line : %u\n", lCount);
printf ("word : %u\n", wCount);
printf ("char : %u\n", cCount);
return 0;
}