Working version of ex22

Makefile

@@ -1,12 +1,17 @@
 CFLAGS=-Wall -g -DNDEBUG
 
-EXERCISES = $(patsubst %.c,%,$(shell ls ex*.c | grep -v ex19))
+EXERCISES = $(patsubst %.c,%,$(shell ls ex*.c | egrep -v "ex(19|22)"))
 
 
-all: $(EXERCISES)
+all: $(EXERCISES) ex22_main
 	$(MAKE) -f ex19.mk
 
 
+ex22_main: ex22.c ex22_main.c ex22.h
+	$(CC) $(CFLAGS) -c -o ex22.o ex22.c
+	$(CC) $(CFLAGS) ex22_main.c ex22.o -o $@
+
+
 test: all
 	$(MAKE) -f ex19.mk test
 

ex22.c

@@ -0,0 +1,35 @@
+#include <stdio.h>
+#include "ex22.h"
+#include "dbg.h"
+
+int THE_SIZE = 1000;
+
+static int THE_AGE = 37;
+
+
+int get_age()
+{
+    return THE_AGE;
+}
+
+
+void set_age(int age)
+{
+    THE_AGE = age;
+}
+
+
+double update_ratio(double new_ratio)
+{
+    static double ratio = 1.0;
+
+    double old_ratio = ratio;
+    ratio = new_ratio;
+
+    return old_ratio;
+}
+
+void print_size()
+{
+    log_info("I think size is: %d", THE_SIZE);
+}

ex22.h

@@ -2,7 +2,7 @@
 #define _ex22_h
 
 // makes THE_SIZE in ex22.c available to other .c files
-extern int THE_SIZE;
+int THE_SIZE;
 
 // gets and sets an internal static variable in ex22.c
 int get_age();

ex22_main.c

@@ -0,0 +1,56 @@
+#include "ex22.h"
+#include "dbg.h"
+
+const char *MY_NAME = "Zed A. Shaw";
+
+
+void scope_demo(int count)
+{
+    log_info("count is: %d", count);
+
+    if(count > 10) {
+        int count = 100;  // BAD! BUGS!
+
+        log_info("count in this scope is %d", count);
+    }
+
+    log_info("count is at exit: %d", count);
+
+    count = 3000;
+
+    log_info("count after assign: %d", count);
+}
+
+
+int main(int argc, char *argv[])
+{
+    // test out THE_AGE accessors
+    log_info("My name: %s, age: %d", MY_NAME, get_age());
+
+    set_age(100);
+
+    log_info("My age is now: %d", get_age());
+
+    // test out THE_SIZE extern
+    log_info("THE_SIZE is: %d", THE_SIZE);
+    print_size();
+
+    THE_SIZE = 9;
+
+    log_info("THE_SIZE is now: %d", THE_SIZE);
+    print_size();
+
+    // test the ratio function static
+    log_info("Ratio at first: %f", update_ratio(2.0));
+    log_info("Ratio again: %f", update_ratio(10.0));
+    log_info("Ratio once more: %f", update_ratio(300.0));
+
+    // test the scope demo
+    int count = 4;
+    scope_demo(count);
+    scope_demo(count * 20);
+
+    log_info("count after calling scope_demo: %d", count);
+
+    return 0;
+}