fix formatting

Author: brownsarahm

_practice/2023-11-16.md

@@ -5,7 +5,7 @@
     1. Compare them in terms of time (assume that each gate requires one unite of time)
     1. Compare them in terms of space/cost by counting the total number of gates required.
     ```
-3. Add {index}`bitwise.md` to your kwl and write the bitwise operations required for the following transformations (replace the `(_)` with a bitwise operator (`&, |, ^, >>, <<`)):
+3. Add {index}`bitwise.md` to your kwl and write the bitwise operations required for the following transformations (replace the `(_)` with a bitwise operator (`&, |, ^, >>, <<, ~`)):
     ```
     4 (_) 128
     12493 (_) -12494

notes/2023-11-07.md

@@ -6,53 +6,31 @@ kernelspec:
 
 # Linking and Object file binary representation
 
-```{important}
-I am behind on this, filling in this using notes from previous semesters and making a PR (only the first, not a duplicate) can be an explore badge. 
-```
-
-
-```{code-cell} bash
-:tags: ["skip-execution"]
-ls
-```
+## Why is the linking step important?
 
-```{code-block} console
-fa23-kwl-brownsarahm		ghic				test
-fall2023			github-inclass-fa23-brownsarahm	tiny-book
-```
+Let's make an empty folder to work with.  I made my in my `inclass/sytems` folder. 
 
 
 ```{code-cell} bash
 :tags: ["skip-execution"]
 mkdir cexample
 ```
 
-```{code-block} console
-```
-
+and then go in that new folder
 
 ```{code-cell} bash
 :tags: ["skip-execution"]
 cd cexample/
 ```
 
-```{code-block} console
-```
-
+We are going to make two files, first 
 
 ```{code-cell} bash
 :tags: ["skip-execution"]
 nano main.c
 ```
 
-```{code-block} console
-```
-
-
-```{code-cell} bash
-:tags: ["skip-execution"]
-cat main.c 
-```
+and put this content in the file: 
 
 ```C
 /* Used to illustrate separate compilation.
@@ -72,19 +50,14 @@ void main () {
 ```
 
 
+And then make a second file: 
+
 ```{code-cell} bash
 :tags: ["skip-execution"]
 nano help.c
 ```
 
-```{code-block} console
-```
-
-
-```{code-cell} bash
-:tags: ["skip-execution"]
-cat help.c 
-```
+with the contents that describes two functions: 
 
 ```C
 /* Used to illustrate separate compilation
@@ -118,12 +91,15 @@ int product (int n) {
 }
 ```
 
+First we can make the two objects:
 
 ```{code-cell} bash
 :tags: ["skip-execution"]
 gcc -Wall -g -c main.c 
 ```
 
+but here we get an error:
+
 ```{code-block} console
 main.c:8:1: warning: return type of 'main' is not 'int' [-Wmain-return-type]
 void main () {
@@ -144,31 +120,20 @@ main.c:13:56: error: implicit declaration of function 'product' is invalid in C9
 ```
 
 
-```{code-cell} bash
-:tags: ["skip-execution"]
-man gcc
-```
-
-```{code-block} console
-No manual entry for gcc
+We can get around this, by telling main about the functions by adding
+```C
+int sum(int n);
+int product (int n);
 ```
-
+to the `main.c`
 
 ```{code-cell} bash
 :tags: ["skip-execution"]
 nano main.c 
 ```
 
-```{code-block} console
-```
-
-
-```{code-cell} bash
-:tags: ["skip-execution"]
-cat main.c 
-```
-
-```{code-block} console
+so that it is like this: 
+```C
 /* Used to illustrate separate compilation.
 Created: Joe Zachary, October 22, 1992
 Modified:
@@ -187,7 +152,7 @@ void main () {
 }
 ```
 
-
+Now we can make this object file
 ```{code-cell} bash
 :tags: ["skip-execution"]
 gcc -Wall -g -c main.c 
@@ -203,7 +168,7 @@ void main () {
 int
 1 warning generated.
 ```
-
+we get a warning, but that's okay
 
 ```{code-cell} bash
 :tags: ["skip-execution"]
@@ -214,6 +179,7 @@ ls
 help.c	main.c	main.o
 ```
 
+If we try to make this an executable, we cannot because then it looks for what those functions are supposed to do, but it cannot do that yet. 
 
 ```{code-cell} bash
 :tags: ["skip-execution"]
@@ -230,34 +196,22 @@ ld: symbol(s) not found for architecture x86_64
 clang: error: linker command failed with exit code 1 (use -v to see invocation)
 ```
 
+So, we make the object file for the helper functions
 
 ```{code-cell} bash
 :tags: ["skip-execution"]
 gcc -Wall -g -c help.c 
 ```
 
-```{code-block} console
-```
-
-
-```{code-cell} bash
-:tags: ["skip-execution"]
-ls
-```
-
-```{code-block} console
-help.c	help.o	main.c	main.o
-```
 
+Now, we can finally link and make it executble:
 
 ```{code-cell} bash
 :tags: ["skip-execution"]
 gcc -o demo main.o help.o -lm
 ```
 
-```{code-block} console
-```
-
+and we can run our program
 
 ```{code-cell} bash
 :tags: ["skip-execution"]
@@ -271,31 +225,21 @@ The product of the first n integers is 120
 ```
 
 
-```{code-cell} bash
-:tags: ["skip-execution"]
-8
-```
+````{tip}
+One reason we split code is to make it readable, but another reason is what we just did.  We can compile each file separately, when your code is large and compiling takes a long time, splitting it will mean you only have to recompile the file(s) you have recently changed and relink, instead of recompiling everything.
+````
 
-```{code-block} console
--bash: 8: command not found
-```
+If we edit, 
 
 
 ```{code-cell} bash
 :tags: ["skip-execution"]
 nano main.c
 ```
 
-```{code-block} console
-```
-
-
-```{code-cell} bash
-:tags: ["skip-execution"]
-cat main.c
-```
+to look like the following: 
 
-```{code-block} console
+```C
 /* Used to illustrate separate compilation.
 Created: Joe Zachary, October 22, 1992
 Modified:
@@ -314,6 +258,10 @@ void main () {
 }
 ```
 
+We added an `!` so it is just different. 
+
+If we run again, it is not different. 
+
 
 ```{code-cell} bash
 :tags: ["skip-execution"]
@@ -326,6 +274,7 @@ The sum of the first n integers is 28
 The product of the first n integers is 5040
 ```
 
+Now, we need to recompile the main file. 
 
 ```{code-cell} bash
 :tags: ["skip-execution"]
@@ -343,15 +292,14 @@ int
 1 warning generated.
 ```
 
+and then relink them into an executable
 
 ```{code-cell} bash
 :tags: ["skip-execution"]
 gcc -o demo main.o help.o -lm
 ```
 
-```{code-block} console
-```
-
+for the changes to apply
 
 ```{code-cell} bash
 :tags: ["skip-execution"]
@@ -364,6 +312,7 @@ The sum of the first n integers is 36
 The product of the first n integers is 40320
 ```
 
+We see that this makes the  executble and the two object files
 
 ```{code-cell} bash
 :tags: ["skip-execution"]
@@ -381,24 +330,14 @@ drwxr-xr-x  9 brownsarahm  staff    288 Nov  7 12:37 ..
 -rw-r--r--  1 brownsarahm  staff   2400 Nov  7 12:53 main.o
 ```
 
-
-```{code-cell} bash
-:tags: ["skip-execution"]
-ls
-```
-
-```{code-block} console
-demo	help.c	help.o	main.c	main.o
-```
+We can change the name of the executable with the `-o` option. 
 
 
 ```{code-cell} bash
 :tags: ["skip-execution"]
 gcc -o sumProd main.o help.o -lm
 ```
 
-```{code-block} console
-```
 
 
 ```{code-cell} bash