C program to remove all characters from string except alphabets

June 24, 2020

Removing all characters from string except alphabets.

In this article we will learn how to code a C program to remove all characters from string except alphabets. In the process to do this all the special characters (!,@,#,etc.) and numeric characters (1,2,3,etc.) need to removed from the string. To remove the characters we will check each characters of the string , if the character checked found to be a non alphabetical character then we will remove the character and store the remaining string as it is. We will iterate this step through a for loop until every non alphabet character is removed.

Algorithm:

Initialize the variables.
Accept the input.
Initialize a for loop.
Iterate each character through the loop.
Remove non alphabetical characters
Terminate for loop.
Print result.

C programming code to remove all characters from string except alphabets

#include <stdio.h>
int main()
{
    //Initializing variable.
    char str[100];
    int i, j;
    
     //Accepting input.
    printf(" Enter a string : ");
    gets(str);

     //Iterating each character and removing non alphabetical characters.
    for(i = 0; str[i] != '\0'; ++i)
    {
        while (!( (str[i] >= 'a' && str[i] <= 'z') || (str[i] >= 'A' && str[i] <= 'Z') || str[i] == '\0') )
        {
            for(j = i; str[j] != '\0'; ++j)
            {
                str[j] = str[j+1];
            }
            str[j] = '\0'; 
        }
    }
     //Printing output.
    printf(" After removing non alphabetical characters the string is :");
    puts(str);
    return 0;
}

Output:
Enter a string : *1prep_insta*
After removing non alphabetical characters the string is :prepinsta