Add 2020/yang/try.sh + format/typo checks

The Makefile also has been updated with a new rule to compile the C++
code the author provided which can preprocess the output of the program
to make it more acceptable to some compilers.

Format/typo check README.md file.

This should complete 2020! There might be another change in another year
but besides that and the YYYY/README.md files the review of all entries
can be mostly considered done (mostly because I will probably do a very
quick pass but this pass is not important one way or another).

2020/yang/try.sh

@@ -0,0 +1,87 @@
+#!/usr/bin/env bash
+#
+# try.sh - demonstrate IOCCC winner 2020/yang
+#
+
+# make sure CC is set so that when we do make CC="$CC" it isn't empty. Doing it
+# this way allows us to have the user specify a different compiler in an easy
+# way.
+if [[ -z "$CC" ]]; then
+    CC="cc"
+fi
+
+make CC="$CC" all >/dev/null || exit 1
+
+# clear screen after compilation so that only the entry is shown
+clear
+
+# we will use hexdump later if it's installed
+HEXDUMP="$(type -P hexdump)"
+
+echo "Getting usage:"
+echo "$ ./prog" 1>&2
+./prog
+echo 1>&2
+
+read -r -n 1 -p "Press any key to continue: "
+echo 1>&2
+echo "$ echo \"International Obfuscated C Code Contest 2020\" | ./prog 23209 > code.c" 1>&2
+echo "International Obfuscated C Code Contest 2020" | ./prog 23209 > code.c
+echo 1>&2
+
+read -r -n 1 -p "Press any key to show code.c (space = next page, q = quit): "
+echo 1>&2
+less -rEXF code.c
+echo 1>&2
+
+# compile without a PIN
+echo "Trying to compile without a PIN:"
+echo 1>&2
+echo "$ cc code.c -o decode" 1>&2
+cc code.c -o decode
+echo 1>&2
+echo "As you can see, you must compile with -DPIN=<number>" 1>&2
+
+if [[ -n "$HEXDUMP" ]]; then
+    # compile with the wrong pin if hexdump is installed
+    echo 1>&2
+    echo "Compiling with wrong PIN: cc -DPIN=555 code.c -o wrongcoded" 1>&2
+    cc -DPIN=555 code.c -o wrongcoded	 # wait for it ...
+    read -r -n 1 -p "Press any key to run wrongcoded: "
+    echo 1>&2
+    ./wrongcoded | "$HEXDUMP" -C
+fi
+
+read -r -n 1 -p "Press any key to compile with a good PIN: "
+echo 1>&2
+# compile with a PIN
+echo "$ cc -DPIN=23209 code.c -o decoded" 1>&2
+cc -DPIN=23209 code.c -o decoded
+read -r -n 1 -p "Press any key to run: ./decoded: "
+echo 1>&2
+./decoded
+
+
+read -r -n 1 -p "Press any key to continue: "
+echo 1>&2
+echo "$ echo \"Hello, world!\" | ./prog 56789 > encoded.c" 1>&2
+echo "Hello, world!" | ./prog 56789 > encoded.c
+echo 1>&2
+
+read -r -n 1 -p "Press any key to show encoded.c (space = next page, q = quit): "
+echo 1>&2
+less -rEXF encoded.c
+echo 1>&2
+
+read -r -n 1 -p "Press any key to compile with PIN 56789: "
+echo 1>&2
+echo "$ cc -DPIN=56789 encoded.c -o decoded" 1>&2
+cc -DPIN=56789 encoded.c -o decoded
+echo 1>&2
+
+read -r -n 1 -p "Press any key to run decoded: "
+echo 1>&2
+echo "$ ./decoded" 1>&2
+./decoded
+
+rm -f decoded code.c encoded.c