doing extra credit for ch23 ex22

ex22.mk

@@ -1,4 +1,4 @@
-all: ex22_main
+all: ex22_main ex22_ec1
 
 
 ex22_main: ex22_main.o ex22.o

ex22_ec1.c

@@ -0,0 +1,28 @@
+#include <stdio.h>
+#include "dbg.h"
+
+
+int pass_by_value(int n)
+{
+    n = n + 2;
+    return n;
+}
+
+
+int pass_by_reference(int *n)
+{
+    *n = *n + 8;
+    return *n;
+}
+
+
+int main(int argc, char *argv[])
+{
+    int n = 2;
+    log_info("BEGIN: n = %d", n);
+    log_info("By value example: %d", pass_by_value(n));
+    log_info("n = %d", n);
+    log_info("By reference example: %d", pass_by_reference(&n));
+    log_info("n = %d", n);
+    return 0;
+}