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week_1:lecture

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 :

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.

hello world

when green flag clicked → say hellow world“ équivaut en C à :

int main(void) {
  printf("hello, world\n");
}

fonctions

say hello, world

printf("hello, world\n");

loops

forever → say hello world

while (true) {
  printf("hello, world\n");
}

repeat 10 → say hello world

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

variables

set counter to 0 → forever → say counter → change counter by 1

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

boolean expressions

x < y

x < y and y < x

(x < y)
<(x < y) && (y < z))

conditions

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
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");
}

...

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

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

now : cloud9 CS50 IDE

cloud : on someone else computer

week_1/lecture.txt · Last modified: 2016/08/20 22:10 by leo