Added static vars chapter

0x0014_static-variables/0x0014_static-variables.c

@@ -0,0 +1,31 @@
+#include <stdio.h>
+#include "pico/stdlib.h"
+
+int main(void) {
+    stdio_init_all();
+
+    const uint BUTTON_GPIO = 15;
+    const uint LED_GPIO = 16;
+    bool pressed = 0;
+
+    gpio_init(BUTTON_GPIO);
+    gpio_set_dir(BUTTON_GPIO, GPIO_IN);
+    gpio_pull_up(BUTTON_GPIO);
+
+    gpio_init(LED_GPIO);
+    gpio_set_dir(LED_GPIO, GPIO_OUT);
+
+    while (true) {
+        uint8_t regular_fav_num = 42;
+        static uint8_t static_fav_num = 42;
+        
+        printf("regular_fav_num: %d\r\n", regular_fav_num);
+        printf("static_fav_num: %d\r\n", static_fav_num);
+        
+        regular_fav_num++;
+        static_fav_num++;
+        
+        pressed = gpio_get(BUTTON_GPIO);
+        gpio_put(LED_GPIO, pressed ? 0 : 1);
+    }
+}