Designing Games with Game Maker - YoYo Games

{
}
repeat (5) instance_create(random(400),random(400),ball);
While statement
A while statement has the form
while ()
As long as the expression is true, the statement (which can also be a block) is executed. Be
careful with your while loops. You can easily make them loop forever, in which case your game
will hang and not react to any user input anymore.
Example
The following program tries to place the current object at a free position (this is about the
same as the action to move an object to a random position).
{
}
while (!place_free(x,y))
{
}
Do statement
x = random(room_width);
y = random(room_height);
A do statement has the form
do until()
The statement (which can also be a block) is executed until the expression is true. The
statement is executed at least once. Be careful with your do loops. You can easily make them
loop forever, in which case your game will hang and not react to any user input anymore.