Part 2! [https://www.youtube.com/watch?v=ix5jPkxsr7M&list=PLWKjhJtqVAbmGw5fN5BQlwuug-8bDmabi&index=2]

• 6:09 Pseudocode (Again)

18:51 Scratch code Translated C code (to say something)

• parentheses () represent the bubble in Scratch
• printf to print words, f meaning formatted
• print words must be in double quotations ""
• to move print to the next line ala Microsoft Word, you have to type "/n"
• Most lines in C have to end with a semicolon ;
• Scratch bubbles () in C are curly brackets {}

21:15 Scratch code Translated C code, the counter

• set counter to 0 --> int counter = 0;, int meaning integer, the type of variable

21:54 Change counter by 1

• counter = counter + 1 (Copy the value on the right to the value on the left)
• or, counter += 1;, counter++;

25:53 Whitespace

• whitespace does not matter to the computer

29:06 == to represent Equal

• = to represent assignment, == represents equality

32:33 Scratch code Loop Translated to C

• forever say hello world --> while { printf ("hello world/n") }
• while wants you to ask a question every time it loops
• if the answer is yes, it is going to run the loop
  • so change while to while (true) to create a loop

36:22 Repeat 50 in Scratch Translated to C

• repeat = for ("For now")
• Use a variable so for will only repeat 50 times

37:30

• for (int i = 0;)
• what this means: create a variable named i, store integers in i, and set initial value to 0

37:57 Why computers count from 0

• Aside from negative values, 0 is the lowest number in binary

38:48

• for (int i = 0; i <50; i++)
• what this does: set i to 0 and prepare to store integers in it, check the condition just in case the value is larger than initialized
• after executing the lines of code, i++ means i will increment by 1 meaning i = 1 and so on
• Note: it will stop at 50 because 51 would be < 50

40:48 Scratch input to C

• Scratch
  • Ask (What's your name?) and wait
    • say (answer)
• C
  • new function called get_string
    • underscore is convention in C, you can't use spaces in names of functions
  • get_string("What's your name?/n")
• A string in a programming language is a sequence of characters
  • anything between the double quotes is a stringin C
  • ✔ n means end of line, as before

42:21 Answer variable for the Return Value

• answer = get_string("What's your name?/n")
• To be more precise, string answer = get_string("What's your name?/n")
  • What this means: give me a string, call it answer, and assign what is to the right
    • What is to the right is whatever get_string comes back with, and is stored from right to left

43:13 Saying the Answer (Person's Name)

• printf ("%s", answer);
• what this means: printf is being told to print out a string that looks like " "
• percent S is a placeholder, with S meaning string
  • So the placeholder is telling printf that it is going to give a string to plug in to the first input
    • That string being the variable answer

45:03 Asking and saying, Hello, Name

• string answer = get_string("What's your name?/n");
• printf("hello, %s", answer);

49:50 CS50 Sandbox

• C files end in .c

52:06 Converting Source Code (like C, codes humans have written) to Machine Code (like binary, code "hardwired from the factory")

• 53:07 Other humans have written programs called a compiler that turns source code into machine code

54:03 $ Prompt

• A dollar sign is typically used represent a prompt
• Terminal window sends commands to the computer