Week 5

 

 

(cheat sheet)

 

Task for today

Create a simple movement script for 2D platformer

  • More left, right, and jump

 

 

James’ Script

img_7402

 

  • Define Class Variables

private float moveSpeed; 

  • Start method used to define values of those variables we defined before.

moveSpeed = 2.0f;

TOO Lost and Confused!!

Did my own research to help me understand how to solve the task.

STRUCTURE OF A PROGRAM

Statement – Write sentences to convey to the compiler to tell them to do a task

; terminates a C++ statement

3 TYPES OF STATEMENTS

1
2
3
int x;
x = 5;
std::cout << x;
DECLARATION STATEMENTS

int x; 

  • This is a declaration statement – Telling the compiler x is a variable
  • Variable is the name for the memory place its held.
  • Variables must be declared before use – Meaning the compiler needs to know the pace to get the info from.
ASSIGNMENT STATEMENTS

x = 5;

  • Computer knows that x = 5
OUTPUT STATEMENT

std::cout << x;

  • Prints x onto the screen.

EXPRESSIONS

x = 2+3;

  • x can be equal to an equation, though the answer to the equation will e assigned to x.
  • So x = 2+3 , 2+ 3 = 5 and so x= 5 and this will be stored.
  • Type of assigned statement
  • Can include ‘values (such as 2), variables (such as x), operators (such as +) and functions (which return an output value based on some input value)’

FUNCTIONS

  • Group of statements
  • Must contain main – refers to special function
  • Statements done in order – first first, second line second etc.

LIBRARIES AND C++ LIBRARIES

  • Library = collection of precompiled code – Function
  • Extend what the program can do.
  • C++ Standard Library – Provides additional functionality

iostream is most common library – Allows you to write to the screen and get input

screen-shot-2016-10-25-at-11-52-24

PREPROCESSOR DIRECTIVE
  • Special type of statement
  • Refers to line 1 of this code
  • Tells compiler to add contents of iosteam header to program
SECOND LINE

int main ()

{

}

  • Declare main function

std::cout <<“Hello world!”;

  • First statement – output statement

return 0;

  • RETURN STATEMENT – “

    When an executable program finishes running, the main() function sends a value back to the operating system that indicates whether it was run successfully or not.

    This particular return statement returns the value of 0 to the operating system, which means “everything went okay!”. Non-zero numbers are typically used to indicate that something went wrong, and the program had to abort. We will discuss return statements in more detail when we discuss functions”

 

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