add original source

source/listing_5.3.cpp

@@ -0,0 +1,17 @@
+#include <iostream>
+
+void foo(int a,int b)
+{
+    std::cout<<a<<”,”<<b<<std::endl;
+}
+
+int get_num()
+{
+    static int i=0;
+    return ++i;
+}
+
+int main()
+{
+    foo(get_num(),get_num());
+}