C program to remove all characters except letters from the string

Comprehensive Collection of C Programming Examples

In this example, you will learn how to remove all characters except letters from the string entered by the user.

To understand this example, you should understand the followingC language programmingTopic:

• C array

• C language string

• C for loop

• C while and do ... while loops

Remove all characters except letters from the string

#include <stdio.h>
int main() {
　　　char line[150];
　　　
　　　printf("Enter a string: ");
　　　fgets(line, sizeof(line), stdin);　//Accept input
　　　for (int i = 0, j; line[i] != '\0';　++i) {
　　　　//If the character is not a letter, then enter the loop
　　　　//It is not a null character
　　　　　　while (!(line[i] >= 'a' && line[i] <= 'z') && !(line[i] >= 'A' && line[i] <= 'Z') && !(line[i] == '\0')) {
　　　　　　　　　for (j = i; line[j] != '\0';　++j) {
　　　　　　　　　　　　//If the jth element of line is not a letter
　　　　　　　　　　　　//to the element at index j　+　1assign the value of the element at index j
　　　　　　　　　　　　line[j] = line[j　+　1];
　　　　　　　　　}
　　　　　　　　　line[j] = '\0';
　　　　　　}
　　　}
　　　printf("Output string: ");
　　　puts(line);
　　　return 0;
}

Output result

Enter a string:　n2'h-o@84oo./
Output string:　w3codebox

This program takes a string input from the user and stores it in the line variable. Then, it uses a for loop to traverse the characters of the string.

If the character in the string is not a letter, it will be removed from the string, and the remaining characters will be moved to the left.1positions.

Comprehensive Collection of C Programming Examples