Project: Array Utilities Unit
Unit: DelphiDabbler.Lib.ArrayUtils
Record: TArrayUtils
Applies to: ~>0.1
class procedure MinMax<T>(const A: array of T;
const AComparer: TComparison<T>; out AMinValue, AMaxValue: T);
overload; static;
class procedure MinMax<T>(const A: array of T;
AComparer: IComparer<T>; out AMinValue, AMaxValue: T);
overload; static;
class procedure MinMax<T>(const A: array of T; out AMinValue, AMaxValue: T);
overload; static;
Finds the minimum and maximum values of a non empty array.
Parameters:
A - The array to be examined.
AComparer - An optional function or object that can be used to compare two values. Used to compare the elements of the arrays to each other.
If AComparer is provided it must be one of:
If this parameter is omitted then the default comparer defined by the TComparer<T>.Default method from the Delphi’s System.Generics.Defaults unit is used.
MinValue - Set to the minimum value of A when the method returns.
MaxValue - Set to the maximum value of A when the method returns.
Precondition:
Using an equality comparer function:
procedure MinMax_Eg1;
var
A: TArray<Integer>;
MinVal, MaxVal: Integer;
ComparerFn: TComparison<Integer>;
begin
A := TArray<Integer>.Create(1, 2, 3, 4, 2, 3, 2);
ComparerFn := function(const Left, Right: Integer): Integer
begin
Result := Left - Right;
end;
TArrayUtils.MinMax<Integer>(A, ComparerFn, MinVal, MaxVal);
Assert(MinVal = 1);
Assert(MaxVal = 4);
end;
Using an equality comparer object:
procedure MinMax_Eg2;
var
A: TArray<string>;
MinVal, MaxVal: string;
ComparerObj: IComparer<string>;
begin
A := TArray<string>.Create('a', 'b', 'c', 'd', 'c', 'a');
ComparerObj := TDelegatedComparer<string>.Create(CompareStr);
TArrayUtils.MinMax<string>(A, ComparerObj, MinVal, MaxVal);
Assert(MinVal = 'a');
Assert(MaxVal = 'd');
end;