Programming Example
C Program to Remove all Characters in a String Except Alphabet
This program takes a strings from user and removes all characters in that string except alphabets.
#include<stdio.h>
int main()
{
char line[150];
int i, j;
printf("Enter a string: ");
gets(line);
for(i = 0; line[i] != '\0'; ++i)
{
while (!( (line[i] >= 'a' && line[i] <= 'z') || (line[i] >= 'A' && line[i] <= 'Z') || line[i] == '\0') )
{
for(j = i; line[j] != '\0'; ++j)
{
line[j] = line[j+1];
}
line[j] = '\0';
}
}
printf("Output String: ");
puts(line);
return 0;
}Enter a string: p2'r-o@gram84./
Output String: program
This program takes a string from the user and stored in the variable line.
The, within the for loop, each character in the string is checked if it's an alphabet or not.
If any character inside a string is not a alphabet, all characters after it including the null character is shifted by 1 position to the left.
First read the algorithm, then study the program code line by line. After that, compare the code with the output and finally go through the explanation. This approach helps learners understand both the logic and the implementation properly.
After understanding this example, try to rewrite the same program without looking at the code. Then change some values or logic and run it again. This helps improve confidence and keeps learners engaged on the page for longer.