写了联合体演示程序

ex35/Makefile

@@ -0,0 +1,4 @@
+CFLAGS=-Wall -g
+
+clean:
+	rm -f ex35

ex35/ex35.c

@@ -17,4 +17,42 @@ struct Variant {
 
 typedef struct Variant Variant;
 
+void Variant_print(Variant *var)
+{
+    switch (var -> type) 
+    {
+        case TYPE_INT:
+            printf("INT: %d\n", var -> data.as_integer);
+            break;
+        case TYPE_FLOAT:
+            printf("FLOAT: %f\n", var -> data.as_float);
+            break;
+        case TYPE_STRING:
+            printf("STRING: %s\n", var -> data.as_string);
+            break;
+        default:
+            printf("UNKNOWN TYPE: %d", var -> type);
+    }
+}
 
+int main (int argc, char *argv[])
+{
+    Variant a_int = {.type = TYPE_INT, .data.as_integer = 100};
+    Variant a_float = {.type = TYPE_FLOAT, .data.as_float = 100.34};
+    Variant a_string = {.type = TYPE_STRING, .data.as_string = "YO DUDE!"};
+
+    Variant_print(&a_int);
+    Variant_print(&a_float);
+    Variant_print(&a_string);
+
+    // here's how you access them
+    a_int.data.as_integer = 200;
+    a_float.data.as_float = 2.345;
+    a_string.data.as_string = "Hi there.";
+
+    Variant_print(&a_int);
+    Variant_print(&a_float);
+    Variant_print(&a_string);
+
+    return 0;
+}