delphi custom formulas

If it's just four operations.

You can refer to the Pascal version of Data Structures

There are four algorithms that implement it.

Then make a rule, the formula variable sequence x,y,z,..Serial letters to meet the maximum parameter requirements.

Variable parameters are provided when called, and the parameters are replaced by a sequence of formula variables.

Function prototypes are suggested as follows:

varriant function operation(expressions: string,..

begin/ 1.Replace the x,y,z values.

2.The replaced string performs four operations.

3.Returns a soft type value.

end;experssions: Templates for your calculated expressions, i.e. formulas.

For variadics, let's use strings uniformly.

For example, i = operation('y+(x*','','3');

i.e. x = , y = 3

What does e stand for? Look at the formula in your example, if it happens to be implemented in delphi.

You take the formula x and pass it to a function function f(x:string): string, in which stringreplace(x,'a','%0:

d', [rfreplaceall]), and replace b2 with %1:d, replace c3, and replace d.

The returned string is something like %0:d div %1:d +%2:

d should be used when the time comes, just format(f(x),[a,b,c,d]) if you write a formula that is written casually, for example, divide with %, replace it with one more time, and replace it with div. Oh, note that divs are integer divisions, and if they are floating-point divisions, they need to be used

I didn't pay attention to this just now, sorry.

You're still going to use all floating-point ones, and then replace div with , and then d %3:f

If you want to use this function in other units as well.

It's defined in public.

public

function get_item_list(tbname, fdname: string; alist: tstrings): boolean;

Then write the ** of the implementation under implementation!

Use before other units are called!

tform1 = class(tform)button1: tbutton;

function button1click(sender: tobject);

private

private declarations }function a(b:string):string;Generally, Hui Qingchun is written on this line, and then ctrl+c, write ** below.

If you want the button to execute, write a() directly in the button's bleed event'Hello');This leak is resistant to samples.

protected

public

public declarations }end;function :string):string;

b;end;function : tobject);

begina('Hello');

end;

You can take different formulas, in the order in which they are calculated, step by step. Distinguish which are specifications and which are constants. parentheses, etc., that's parsing. Its functions should be written according to the actual situation.

Formula parsing controls, go to the box.

Or use the strategy mode, one item and one algorithm class.

For example, if you want to write a function func, according to you, it should be defined as procedure rather than function in delphi, and the specific writing should be as follows:

procedure func(edate,sdate:tdatetime;

i, k:integer;

var bsdate,bedate:tdatetime);

Declare in private or uses.

Then write the implementation in the place of implementation; Or put it separately in a unit single defeat hall Yuan Chi Ling file, quote Chayin in uses, and then quote directly.

Declare in private.

Then write the implementation in the place of implementation;