Doing unit conversion prog, touching up Makefile

d/prog-lang-book/Makefile

@@ -4,4 +4,6 @@ ALL_TARGETS := $(patsubst src/%.d,bin/%,$(ALL_SOURCES))
 bin/%: src/%.d
 	dmd $^ -of$@
 
-$(ALL_TARGETS): $(ALL_SOURCES)
+all: $(ALL_TARGETS)
+
+.PHONY: all

d/prog-lang-book/src/height_conversions.d

@@ -0,0 +1,19 @@
+/*
+   Compute heights in centimeters for a range of heights
+   expressed in feet and inches
+ */
+import std.stdio;
+
+void main() {
+    // Values unlikely to change soon
+    immutable inchesPerFoot = 12;
+    immutable cmPerInch = 2.54;
+
+    // Loop'n write
+    foreach (feet; 5 .. 7) {
+        foreach (inches; 0 .. inchesPerFoot) {
+            writeln(feet, "'", inches, "''\t",
+                (feet * inchesPerFoot + inches) * cmPerInch);
+        }
+    }
+}