diff --git a/c_modern_approach/Preprocessor/celcius.c b/c_modern_approach/Preprocessor/celcius.c
index 9f1678e..31b8532 100644
--- a/c_modern_approach/Preprocessor/celcius.c
+++ b/c_modern_approach/Preprocessor/celcius.c
@@ -2,14 +2,17 @@
 #include <stdio.h>
 
 #define FREEZING_PT 32.0f
-#define SCALE_FACTOR (5.0f / 9.0f)
+#define BEGIN {
+#define END }
 
-int main(void) {
+int main(void)
+BEGIN
   float farenheit, celsius;
 
   printf("Enter Fahrenheit temperature: ");
   scanf("%f", &farenheit);
 
+  #define SCALE_FACTOR (5.0f / 9.0f)
   celsius = (farenheit - FREEZING_PT) * SCALE_FACTOR;
 
   printf("Celcius equivalent is: %.1f\n", celsius);
diff --git a/c_modern_approach/Preprocessor/double_hashtag_op.c b/c_modern_approach/Preprocessor/double_hashtag_op.c
index 08dcae9..9cba086 100644
--- a/c_modern_approach/Preprocessor/double_hashtag_op.c
+++ b/c_modern_approach/Preprocessor/double_hashtag_op.c
@@ -1,7 +1,15 @@
 #include <stdio.h>
-#define MK_ID(n) i##n
+#define MK_ID(n) kakulya_##n
+
+#define GENERIC_MAX(type)                                                      \
+  type type##_max(type x, type y) { return x > y ? x : y; }
+
+GENERIC_MAX(float);
+/* The macro above will transorf into something like following:
+ * float float_max(float x, float y) { return x > y ? x : y; }
+ */
 
 int main(int argc, char *argv[]) {
-  int MK_ID(1); // This converts to `int i1`
-  printf("%d", i1);
+  int MK_ID(1); // This converts to `int kakulya_1`
+  printf("%d", kakulya_1);
 }
diff --git a/c_modern_approach/Preprocessor/parametrized_macroses.c b/c_modern_approach/Preprocessor/parametrized_macroses.c
index c4905bf..78f3bba 100644
--- a/c_modern_approach/Preprocessor/parametrized_macroses.c
+++ b/c_modern_approach/Preprocessor/parametrized_macroses.c
@@ -1,9 +1,13 @@
 #include <stdio.h>
 #define MAX(x, y) ((x) > (y) ? (x) : (y))
+#define IS_EVEN(n) ((n) % 2 == 0)
+#define IS_EVEN_STR(n) ((n) % 2 == 0 ? "yes" : "no")
 
 int main(int argc, char *argv[]) {
   int j, k;
   j = 10;
   k = 20;
-  printf("%d", MAX(j, k));
+  printf("%d\n", MAX(j, k));
+  printf("%d is even: %d\n", j, IS_EVEN(j));
+  printf("%d is even? %s\n", j, IS_EVEN_STR(j));
 }
diff --git a/c_modern_approach/Preprocessor/playground.c b/c_modern_approach/Preprocessor/playground.c
index 048d3aa..c669fff 100644
--- a/c_modern_approach/Preprocessor/playground.c
+++ b/c_modern_approach/Preprocessor/playground.c
@@ -1,9 +1,10 @@
 #include <stdio.h>
 #define PRINT_INT(n) printf(#n " AND " #n " = %d\n", n)
 
-int main(void) {
-  int i, j;
-  i = 10;
-  j = 20;
-  PRINT_INT(i / j);
+int main(void) 
+{
+  unsigned long int k = 10;
+  printf("sizeof k: %lu", k);
+  int x = sizeof(int);
+  printf("sizeof k: %d", x);
 }
diff --git a/c_modern_approach/Preprocessor/predefined.c b/c_modern_approach/Preprocessor/predefined.c
new file mode 100644
index 0000000..e98b1d4
--- /dev/null
+++ b/c_modern_approach/Preprocessor/predefined.c
@@ -0,0 +1,8 @@
+#include <stdc-predef.h>
+#include <stdio.h>
+int main() {
+  // printf("%s", __STDC_IEC_559__);
+  // printf("%s", __STDC_IEC_559_COMPLEX__);
+  printf("%d\n", __STDC_VERSION__);
+  printf("%d", __STDC_HOSTED__);
+};
diff --git a/c_modern_approach/Preprocessor/single_hashtag_op.c b/c_modern_approach/Preprocessor/single_hashtag_op.c
new file mode 100644
index 0000000..3045f77
--- /dev/null
+++ b/c_modern_approach/Preprocessor/single_hashtag_op.c
@@ -0,0 +1,11 @@
+#include <stdio.h>
+#define PRINT_INT(n) printf(#n " = %d\n", n)
+
+int main() {
+  int i = 10;
+  PRINT_INT(i);
+}
+
+/* This program with the help of `#` operator will conver #n to string literal
+ * of an argument, so the output of the program will be: i = 10
+ */