check if a string contains only letters in C

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

  int check_for_letters(char *inputString) 
  {
    int i;
    if (inputString[0] == '\0') 
        return 0;
    for (i=0; inputString[i] != '\0'; i++) 
    {
        if (isalpha(inputString[i]) == 0) 
            return 0;
    }
    return 1;
  }

This code checks whether the string contains only letters in C. First, it includes the required libraries and a function declaration. Then, the function checks if the string is empty (returning 0) and iterates through each character with a for loop. It stops when the character is a null character (ending the string) and checks every character with the isalpha() function. If the character is not alpha character, the function immediately returns 0, otherwise it returns 1 at the end.