C Program to Count Alphabets Digits and Special Characters in a String

In this article, we will show you, How to write a C Program to Count Alphabets Digits and Special Characters in a String with example. For this we are going to use Built-in function isalpha, isdigit, and ASCII Codes.

C Program to Count Alphabets Digits and Special Characters in a String Example 1

This program allows the user to enter a string (or character array). And then it will check, how many number of Alphabets, digits, and Special Character inside that string. In this program, we are using the alphabets and digits directly inside the Else If Statement.

/* C Program to count Alphabets Digits and Special Characters in a String */
 
#include <stdio.h>
 
int main()
{
  	char str[100];
  	int i, alphabets, digits, special;
  	i = alphabets = digits = special = 0;
 
  	printf("\n Please Enter any String  :  ");
  	gets(str);
  	
  	while (str[i] != '\0')
  	{
  		if( (str[i] >= 'a' && str[i] <= 'z') || (str[i] >= 'A' && str[i] <= 'Z') )
  		{
  			alphabets++;  	
 		}
  		else if (str[i] >= '0' && str[i] <= '9')
  		{
  			digits++;  	
  		}    
  		else
    		special++;
    	i++;
	}
    printf("\n Number of Alphabets in this String = %d", alphabets);  
	printf("\n Number of Digits in this String = %d", digits);  
	printf("\n Number of Special Characters in this String = %d", special);  	
  
  	return 0;
}

OUTPUT

First we used While Loop to iterate each and every character in a String.

From the above screenshot you can observe that,
str[] = [email protected]!
i = alphabets = digits = special = 0

While Loop First Iteration: while (str[ i ] != 0)
The condition is True because str[0] = H.
Within the While Loop we used Else If Statement to check whether it is a Alphabet, digit, or Special Character.
if( (str[i] >= ‘a’ && str[i] <= ‘z’) || (str[i] >= ‘A’ && str[i] <= ‘Z’) )
=> if( (H >= ‘a’ && H <= ‘z’) || (H >= ‘A’ && H <= ‘Z’) )
From the above if statement, H >= ‘A’ && H <= ‘Z’ condition returns true. So, alphabets++
It means alphabets = 1

Second Iteration: while (str[ 1 ] != 0)
The condition is True because str[1] = i.
if( (i >= ‘a’ && i <= ‘z’) || (i >= ‘A’ && i <= ‘Z’) )
From the above if statement, i >= ‘a’ && i <= ‘z’ condition returns true. So, alphabets++
It means alphabets = 2

Third Iteration: while (str[ 2 ] != 0)
The condition is True because str[2] = @.
if( (@ >= ‘a’ && @ <= ‘z’) || (@ >= ‘A’ && @ <= ‘Z’) ) – Condition Fails
else if (@ >= ‘0’ && @ <= ‘9’)  – Condition Fails
So, it will execute the statement inside the Else block. So, special++
It means special = 1

Do the same for remaining iterations

C Program to Count Alphabets Digits and Special Characters in a String Example 2

In this program we are using For Loop to iterate each and every character in a String. Next, we used the ASCII values to check whether individual character of a string is Alphabet, Digit, or special character. I suggest you to refer ASCII Table to under the ASCII values of each and every character.

/* C Program to count Alphabets Digits and Special Characters in a String */
 
#include <stdio.h>
 
int main()
{
  	char str[100];
  	int i, alphabets, digits, special;
  	alphabets = digits = special = 0;
 
  	printf("\n Please Enter any String :  ");
  	gets(str);
  	
  	for(i = 0; str[i] != '\0'; i++)
  	{
  		if (str[i] >= 48 && str[i] <= 57)
  		{
  			digits++;  	
 		}
  		else if( (str[i] >= 65 && str[i] <= 90) || (str[i] >= 97 && str[i] <= 122) )
  		{
  			alphabets++; 	
  		}    
  		else
    		special++;
	}
    printf("\n Number of Alphabets in this String = %d", alphabets);  
	printf("\n Number of Digits in this String = %d", digits);  
	printf("\n Number of Special Characters in this String = %d", special);  	
  
  	return 0;
}

OUTPUT

C Program to Count Alphabets Digits and Special Characters in a String Example 3

In this example, we are using built-in functions isalpha, and isdigit to check whether each character in a given string is Alphabet or Digit

/* C Program to count Alphabets Digits and Special Characters in a String */
 
#include <stdio.h>
 
int main()
{
  	char str[100];
  	int i, alphabets, digits, special;
  	alphabets = digits = special = 0;
 
  	printf("\n Please Enter any String :  ");
  	gets(str);
  	
  	for(i = 0; str[i] != '\0'; i++)
  	{
  		if (isalpha(str[i]))
  		{
  			alphabets++;  	
 		}
  		else if(isdigit(str[i]))
  		{
  			digits++; 	
  		}    
  		else
    		special++;
	}
    printf("\n Number of Alphabets in this String = %d", alphabets);  
	printf("\n Number of Digits in this String = %d", digits);  
	printf("\n Number of Special Characters in this String = %d", special);  	
  
  	return 0;
}

OUTPUT

C Program to Count Alphabets Digits and Special Characters in a String Example 4

This program is same as the first example but this time we are using the pointers concept.

/* C Program to count Alphabets Digits and Special Characters in a String */
 
#include <stdio.h>
 
int main()
{
  	char str[100];
  	char *s = str;
  	int alphabets, digits, special;
  	alphabets = digits = special = 0;
 
  	printf("\n Please Enter any String : ");
  	gets(str);
  	
  	while (*s)
  	{
  		if( (*s >= 'a' && *s <= 'z') || (*s >= 'A' && *s <= 'Z') )
  		{
  			alphabets++;  	
 		}
  		else if (*s >= '0' && *s <= '9')
  		{
  			digits++;  	
  		}    
  		else
    		special++;
    	s++;
	}
    printf("\n Number of Alphabets in this String = %d", alphabets);  
	printf("\n Number of Digits in this String = %d", digits);  
	printf("\n Number of Special Characters in this String = %d", special);  	
  
  	return 0;
}

OUTPUT

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