alpha in C code example

Example: isalpha c

#include <stdio.h>
#include <ctype.h> //this is isalpha's library

int main(void)
{
  string variable0 = "a";
  if (isalpha(variable1))
  {
    printf("this will print");
  }
  
  string variable1 = 1;
  if (isalpha(variable1))
  {
    printf("this will NOT print");
  }
}