File Scope State

Module state can live at file scope and be updated through small functions.

file_scope_state.c

#include <stdio.h>

static int total = 0;

static void add_points(int points) {
    total += points;
}

int main(void) {
    int bonus = ;
    add_points(4);
    add_points(bonus);

    printf("total=%d\n", total);
    return 0;
}

#include <stdio.h>

static int total = 0;

static void add_points(int points) {
    total += points;
}

int main(void) {
    int bonus = ;
    add_points(4);
    add_points(bonus);

    printf("total=%d\n", total);
    return 0;
}

#include <stdio.h>

static int total = 0;

static void add_points(int points) {
    total += points;
}

int main(void) {
    int bonus = ;
    add_points(4);
    add_points(bonus);

    printf("total=%d\n", total);
    return 0;
}

private state A `static` file-scope variable is shared by functions in the file but hidden from other files.

controlled update Small functions keep changes to that state in one place.