Did a few exersises, most of the way through serial_logger.

function_pointer/src/function_pointer.c

@@ -0,0 +1,26 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+void function0(void) { printf("function 0\n"); }
+void function1(void) { printf("function 1\n"); }
+void function2(void) { printf("function 2\n"); }
+typedef void (*VoidToVoid)(void);
+
+int main(int argc, char *argv[]) {
+    VoidToVoid functions[3] = {function0, function1, function2};
+    if (argc != 2) {
+        printf("one argument only\n");
+        return EXIT_FAILURE;
+    }
+
+    unsigned char index = strtol(argv[1], NULL, 10);
+
+    if (index > 2) {
+        printf("argument must be between 0 and 2\n");
+        return EXIT_FAILURE;
+    }
+
+    functions[index]();
+
+    return EXIT_SUCCESS;
+}