C Programming: Remove characters in String Except Alphabets

Last update on March 20 2025 12:42:41 (UTC/GMT +8 hours)

17. Remove Non-Alphabets

Write a program in C to remove characters from a string except alphabets.

Sample Solution:

C Code:

#include <stdio.h>
#include <string.h>

int main() {
    char str[150]; // Declare a character array to store the string
    int i, j; // Declare variables for iteration

    printf("\n\nRemove characters in String Except Alphabets :\n"); // Display information about the task
    printf("--------------------------------------------------\n");

    printf("Input the string : ");
    fgets(str, sizeof str, stdin); // Read a string from the standard input (keyboard)

    for (i = 0; str[i] != '\0'; ++i) {
        while (!((str[i] >= 'a' && str[i] <= 'z') || (str[i] >= 'A' && str[i] <= 'Z' || str[i] == '\0'))){
            // Loop to remove non-alphabetic characters from the string
            for (j = i; str[j] != '\0'; ++j) {
                str[j] = str[j + 1]; // Shift characters to the left to remove non-alphabetic characters
            }
            str[j] = '\0'; // Set the end of the string after removal
        }
    }

    printf("After removing the Output String : %s\n\n", str); // Display the modified string after removal
	
	return 0; // Return 0 to indicate successful execution of the program
}

Output:

Remove characters in String Except Alphabets :                                                                                
--------------------------------------------------                                                                            
Input the string : W3resource.com                                                                                             
After removing the Output String : Wresourcecom 

Flowchart:

For more Practice: Solve these Related Problems:

• Write a C program to filter a string so that only alphabet characters are retained, removing digits and punctuation.
• Write a C program to copy only the letters from an input string into a new string.
• Write a C program to remove all non-alphabetic characters from a string using ASCII value checks.
• Write a C program to iterate through a string and build a new string containing only alphabetic and space characters.

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