Added readme to 3a

README.md

@@ -41,3 +41,40 @@ cargo run
 ## Description
 
 Will take the string from CODED and output the decoded string into PLAIN
+
+## Analysis
+
+3a with the slice-borrowing will fail with
+
+```
+Running `target/debug/a3_decode`
+Time to decode!
+Decoded:
+
+"But unto the wicked God saith, What hast thou to do to declare  my statutes, or that thou shouldest take my covenant in thy mouth ?\u{0}"
+```
+
+while with branch 3b it detects it at compile time:
+
+```
+error[E0308]: mismatched types
+   --> src/main.rs:13:1
+    |
+13  | / [   0x015e7a47,
+14  | |     0x2ef84ebb,
+15  | |     0x177a8db4,
+16  | |     0x1b722ff9,
+...   |
+143 | |     0xc2e41061
+144 | |         ];
+    | |_________^ expected an array with a fixed size of 132 elements,
+    |             found one with 131 elements
+    |
+    = note: expected type `[u32; 132]`
+               found type `[u32; 131]`
+
+error: aborting due to previous error
+
+error: Could not compile `a3_decode`.
+```
+