C Program to Count number of words,digits,vowels using pointers

#include<stdio.h>
#include<stdlib.h>
#include<ctype.h>
#include<conio.h>

/*low implies that position of pointer is within a word*/
#define low 1 
/*high implies that position of pointer is out of word.*/
#define high 0 

void main()
{
int nob,now,nod,nov,nos,pos=high;
char *s;
nob=now=nod=nov=nos=0;
clrscr();

printf("Enter any string:");
gets(s);

while(*s!='')
{
if(*s==' ')  /* counting number of blank spaces. */
    {
    pos=high;
    ++nob;
    }
else if(pos==high) /* counting number of words. */
    {
    pos=low;
    ++now;
    }

if(isdigit(*s))   /* counting number of digits. */
    ++nod;
if(isalpha(*s))    /* counting number of vowels */
    switch(*s)
        {
        case 'a':
        case 'e':
        case 'i':
        case 'o':
        case 'u':
        case 'A':
        case 'E':
        case 'I':
        case 'O':
        case 'U':
        ++nov;
        break;
        }

/* counting number of special characters */
if(!isdigit(*s)&&!isalpha(*s))
    ++nos;

s++;
}

printf("\nNumber of words %d",now);
printf("\nNumber of spaces %d",nob);
printf("\nNumber of vowels %d",nov);
printf("\nNumber of digits %d",nod);
printf("\nNumber of special characters %d",nos);

getch();
}

Output :

Enter any string : pritesh a taral from c4learn.com

Number of words 5
Number of spaces 4
Number of vowels 9
Number of digits 1
Number of special characters 5

Explanation of Program :

Now we are going to accept string using gets(). We are not using scanf() to accept string because scanf() will accept string only upto whitespace.

printf("Enter any string:");
gets(s);

We are accepting string using character pointer. Now we are checking each character using character pointer and in each loop we are incrementing the character pointer.

while(*s!='')
{
------
------
}

Whenever first space is encountered then number of space counter is incremented by one.

if(*s==' ')
    {
    pos=high;
    ++nob;
    }
else if(pos==high)
    {
    pos=low;
    ++now;
    }

In the if block we are checking that whether our pointer position is within the word or outside the word.