language - Java Trainer

Current details of the language - not for beginners - for experts:

A Program

function void main()  // 'click 'pretty' to format
{
    int x=0;
    x=big(6, 88);
    print("biggest is:   ");
    print (x);
}
function int big(int a, int b)
{
    if(a<b)
    {
        return a;
    }
    else
    {
        return b;
    }
}

This particular incarnation enforces a 'straightjacket' of no globals.

Parameters and return is like Java. We use pass-by-value, using types: int, double, string. A function with no return takes the form:

function void fred(int a)
{
declarations

code
}

Here is 'hello world':

function void main()
{
alert("hello");
}

// for comments ( slash-star comments not allowed)

Declarations

int x=3, sum=23;
int y=9;
double d=2.0;  // must use a   .  in double constants
string name="mike";

Statements

assignment

I / O

Display on 'console screen' - print

Display on 'console screen' then move to next line - printLine

The parameter of the above is a single numeric expression, or a single string (can't join strings)

get an int, double or a string from a popup box: getInt, getString, getDouble. (you need to supply a prompt, and you can type quit to halt the program.)

int n=0;
string s="";
n=getInt("type your age");
s=getString("type your name");
alert(s);

Control Strucs

You must not use a ; at end, as in: while(a>0);

(this is flagged as an error)

You MUST use {...} round statements.

'for' - not available yet.

You must use a boolean expr in if, while

Stuck in a loop? - Every few hundred instructions, a pop-up is displayed warning that the program might be stuck in a loop, asking if you want to quit or not.

Assignment

Normal use of ( .. ) is allowed.

type-checking across = is done.: double = int; is ok. But not int=double;

You can use ++ and --, but only in the form:

n++;
c--;

Operators

/ gives a float result on the rhs, which = converts to int. : will be fixed soon.

Misc