finished chapter 04

k&r/04-funcs-and-prog-struct/04-14.c

@@ -0,0 +1,18 @@
+#include <stdio.h>
+
+#define swap(T, x, y) \
+    do { \
+       T temp; \
+       temp = x, x = y, y = temp; \
+    } while (0) 
+
+/* swap x and y */
+int main()
+{
+    int x, y;
+    x = -1, y = 1;
+    printf("x = %d, y = %d\n", x, y);
+    swap(int, x, y);
+    printf("x = %d, y = %d\n", x, y);
+    return 0;
+}