Mega Code Archive
Variable number of arguments
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Title: Variable number of arguments
Question: In some situations, it can prove to be useful and convient to have a function that can accept X number of parameters.
For example:
At point A you'll write a function to add 3 integers together, and of course it'll only accept three parameters.
At point B, you'll need an identical function, but which can accept 10 integers.
So instead of doing the typical 1 + 2 + 3 + 4 etc. (this can very tedious to do, especially with more than let's say 15 numbers), you'll make a function that can accept as many (or as few) arguements as you'll ever need.
Following is an example of a function that accepts N number of arguements, adds the passed numbers together and returns the result.
Answer:
function AddNumbers( const ArgsList : array of const ) : Integer;
var
ArgsListTyped: array[0..$FFF0 div SizeOf(TVarRec)] of TVarRec absolute ArgsList;
n: Integer;
begin
result := 0;
for n := Low( ArgsList ) to High( ArgsList ) do
begin
with ArgsListTyped[ n ] do
begin
case VType of
vtInteger: result := result + VInteger;
end;
end;
end;
end;
// AddNumbers() will return the sum of all the integers passed to it
{
AddNumbers( [1, 2, 3] ); will return 6
AddNumbers( [4, 5, 6, 7, 8, 9, 10, 11] ); will return 60
}
{ Following code was suggested by Luis Ortega.
Thanks Luis!
}
function AddNumbers( const ArgsList : array of Integer ) : Integer;
var
n: Integer;
begin
result := 0;
for n := Low( ArgsList ) to High( ArgsList ) do
result := result + ArgsList[n];
end;
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