Splitting source code files

[rocksteady]

I have a program that I want to split into two separate source code files, plus a single header file. The first source file should just have the main function that takes care of the input and calls the manipulation function. The header should contain the interface to those functions that the main function can then include.

Here's the code I have so far:

#include<stdio.h>

void update(char);
void print_hist(void);

int main(void)
{
  char c;

  printf("Please enter as many characters as you would like. Press enter or send the EOF character when you are done.\n");
 
  while( (c=getchar()) != EOF) {
    void update(char);
    void print_hist(void);
  }

  return 0;
}

Thanks!

EDIT: I'm working on the manipulation functions now. However, I can't figure out how to make the void update(char) determine whether a character is alphanumeric or not. Can anyone give me some direction?

[Prelude]

Take this and put it in the header:

void update(char);
void print_hist(void);

Replace those lines in the main file with an include of the header. Take the implementations of those functions and put them in a .c file. Correct your main function like so:

while( (c=getchar()) != EOF) {
    update(c);
    print_hist();
}

That's all it takes to separate things into three files.

>I can't figure out how to make the void update(char)
>determine whether a character is alphanumeric or not.
I'm rather partial to the standard isalnum function.

[rocksteady]

Thank you. I was confused on how to insert the call functions, but that's because I didn't really know what a header file was.