1 files changed, 104 insertions, 0 deletions
diff --git a/7segment.c b/7segment.c
new file mode 100644
index 0000000..5b0abaf
--- /dev/null
+++ b/7segment.c
@@ -0,0 +1,104 @@
+/*
+ * Copyright Daniel Jones <daniel@danieljon.es>
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+
+/*
+	A
+	_
+      F| |B
+      G	-
+      E| |C
+	-
+	D
+	
+ A 7 segment display (unsurprisingly) has 7 individual segments that can conveniently make 0-9 and A-F
+ perfect for hexadecimal.
+ The state of a single 7 segment character can also conveniently be stored in 8 bits (a byte, in C a char),
+ almost as if these aren't coincidences (they're not).
+*/
+
+enum segments
+{
+	/* refer to the diagram to know which value represents which segment */
+	SEG_A 	= 1 << 0,
+	SEG_B 	= 1 << 1,
+	SEG_C	= 1 << 2,
+	SEG_D	= 1 << 3,
+	SEG_E	= 1 << 4,
+	SEG_F	= 1 << 5,
+	SEG_G	= 1 << 6,
+};
+
+enum characters
+{
+	CHAR_ZERO	= SEG_A | SEG_B | SEG_C | SEG_D | SEG_E | SEG_F,
+	CHAR_ONE	= SEG_B | SEG_C,
+	CHAR_TWO	= SEG_A | SEG_B | SEG_D | SEG_E | SEG_G,
+	CHAR_THREE	= SEG_A | SEG_B | SEG_C | SEG_D | SEG_G,
+	CHAR_FOUR	= SEG_B | SEG_C | SEG_F | SEG_G,
+	CHAR_FIVE	= SEG_A | SEG_C | SEG_D | SEG_F | SEG_G,
+	CHAR_SIX	= SEG_A | SEG_C | SEG_D | SEG_E | SEG_F | SEG_G,
+	CHAR_SEVEN	= SEG_A | SEG_B | SEG_C,
+	CHAR_EIGHT	= SEG_A | SEG_B | SEG_C | SEG_D | SEG_E | SEG_F | SEG_G,
+	CHAR_NINE	= SEG_A | SEG_B | SEG_C | SEG_D | SEG_F | SEG_G,
+	CHAR_A		= SEG_A | SEG_B | SEG_C | SEG_E | SEG_F | SEG_G,
+	CHAR_B		= SEG_C | SEG_D | SEG_E | SEG_F | SEG_G,
+	CHAR_C		= SEG_A | SEG_D | SEG_E | SEG_F,
+	CHAR_D		= SEG_B | SEG_C | SEG_D | SEG_E | SEG_G,
+	CHAR_E		= SEG_A | SEG_D | SEG_E | SEG_F | SEG_G,
+	CHAR_F		= SEG_A | SEG_E | SEG_F | SEG_G,
+};
+
+void
+printdisplay(char segs)
+{
+	/* line 1 */
+	printf("\t %c\n", (segs & SEG_A) ? '_' : ' ');
+	/* line 2 */
+	printf("\t%c %c\n", (segs & SEG_F) ? '|' : ' ',
+			    (segs & SEG_B) ? '|' : ' ');
+	/* line 3 */
+	printf("\t %c\n", (segs & SEG_G) ? '-' : ' ');
+	/* line 4 */
+	printf("\t%c %c\n", (segs & SEG_E) ? '|' : ' ',
+			    (segs & SEG_C) ? '|' : ' ');
+	/* line 5 */
+	printf("\t %c\n", (segs & SEG_D) ? '-' : ' ');
+}
+
+void
+clear()
+{
+
+	printf("%s", "\033[5;0F");
+	printf("%s", "\033[0J");
+}
+
+char hexcharacters[16] = {CHAR_ZERO, CHAR_ONE, CHAR_TWO, CHAR_THREE, CHAR_FOUR, CHAR_FIVE, CHAR_SIX, CHAR_SEVEN, CHAR_EIGHT, CHAR_NINE,
+			  CHAR_A, CHAR_B, CHAR_C, CHAR_D, CHAR_E, CHAR_F};
+
+int
+main(void)
+{
+	for (int i = 0; i < 16; i++)
+	{
+		printdisplay(hexcharacters[i]);
+		sleep(1);
+		clear();
+	}
+}