update

clang.md

@@ -197,4 +197,38 @@ int main() {
 
 This list goes on, you can find more information about undefined behaviours in this [thesis](https://solidsands.com/wp-content/uploads/Master_Thesis_Vasileios_GemistosFinal.pdf) and in the [C99 Standard](https://www.dii.uchile.cl/~daespino/files/Iso_C_1999_definition.pdf)
 
-## Memory Model in C
+## True or False
+
+There is no explicit `Boolean` type in old-school C. Alternatively, you can use the boolean type in the header file `#include <stdbool.h>` introduced in `C99`.
+
+```c
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+
+int main(void) {
+    bool keep_going = true;  // Could also be `bool keep_going = 1;`
+    while(keep_going) {
+        printf("This will run as long as keep_going is true.\n");
+        keep_going = false;    // Could also be `keep_going = 0;`
+    }
+    printf("Stopping!\n");
+    return EXIT_SUCCESS;
+}
+```
+
+### What evaluates to FALSE in C?
+
+- `0` (integer)
+- `NULL`
+- Basically anything where all the bits are 0 is false
+
+### What evaluates to TRUE in C?
+
+- Anything that isn't false is true
+
+## Pointers in C
+
+Pointers are probably the single largest source of bugs in C, so be careful when you use them.
+
+