|<- [[week_0:Problem set 0]]|[[Lecture, continued]] ->|

=== terminology ===

introduite en semaine 0

  * statement (ex: say hello)
  * loops (repeat 10)
  * boolean expressions (mouse down ?)
  * conditions (if, if else)

===== source code =====

==== source code ====

Source code ? what does it look like ?

CS50 IDE

concepts :

  * compiler : a general term for a piece of software that take source code and produces object code from it ( source code -> compiler -> object code )
  * object code : fancy term for 0 and 1

==== scratch -> C ====

Intéressant : après avoir montré scratch et fait utiliser, montrer l'équivalence en code source en C. Ce qui permet de limiter l'abstraction.

Aussi :

<code>
Le style d'écriture utilisé pour le cours des curly braces est celui-ci :

smthg
{
  //code
}

et non :

smthg {
  // code
}

Peut-être que le style original est plus clair.
</code>
=== hello world ===
when green flag clicked -> say hellow world" équivaut en C à :

<code>
int main(void) {
  printf("hello, world\n");
}
</code>

=== fonctions ===

say hello, world

<code>
printf("hello, world\n");
</code>

=== loops ===

forever -> say hello world

<code>
while (true) {
  printf("hello, world\n");
}
</code>

repeat 10 -> say hello world

<code>
for (int i = 0; i < 10; i++) {
  printf("hello, world\n");
}
</code>

=== variables ===

set counter to 0 -> forever -> say counter -> change counter by 1

<code>
int counter = 0;
while (true) {
  printf("%i\n", counter);
  counter++;
}
</code>

=== boolean expressions ===

x < y

x < y and y < x

<code>
(x < y)
<(x < y) && (y < z))</code>

=== conditions ===

<code>
if x < y -> say x is less than y
else
  if x > y -> say x is greater than y
  else -> say x is equal to y
</code>

<code>
if (x < y) {
  printf("x is less than y\n");
} else if {
  printf("x is greater than y\n");
} else {
  printf("x is equal to y\n");
}
</code>

=== ... ===

<code>
#include <stdio.h>
int main(void) { // (parameter/input)
  printf("hello, world\n"); // statement
}
</code>

previously : CS50 virtual machine with CS50 environment (linux) : make sure everyone have the same environment

now : cloud9 CS50 IDE

cloud : on someone else computer