Add some theory for Basic types section

c_modern_approach/BasicTypes/theory.c

@@ -0,0 +1,22 @@
+#include <stdio.h>
+
+typedef int Kekus;
+
+int main() {
+  unsigned kek;
+  kek = -9;
+  printf("%du\n", kek);
+
+  char ch1 = 'a';
+  char ch2 = 'A';
+  char ch3 = '0';
+  char ch4 = ' ';
+
+  printf("%c : %d\n", ch1, ch1);
+  printf("%c : %d\n", ch2, ch2);
+  printf("%c : %d\n", ch3, ch3);
+  printf("%c : %d\n", ch4, ch4);
+
+  Kekus pips = 192;
+  printf("%d\n", pips);
+}