DelphiBasics
 StrToIntFunction Convert an integer string into an Integer value SysUtils unit
 function StrToInt(IntegerString string):Integer;
Description
The StrToInt function converts an Integer string, IntegerString such as '123' into an Integer.

It supports +ve and -ve numbers, and hexadecimal numbers, as prefixed by \$ or 0x.

Note that for Delphi 7 and possibly other versions of Delphi, you may omit the 0 before the x for hexadecimal values.
Notes
The EConvertError exception is thrown if there are errors in IntegerString, such as trailing blanks, decimal points, invalid decimal or hexadecimal characters.
Related commands
 Integer The basic Integer type IntToStr Convert an integer into a string StrToInt64 Convert an integer string into an Int64 value StrToInt64Def Convert a string into an Int64 value with default StrToIntDef Convert a string into an Integer value with default
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Example code : Converting decimal and hexadecimal numbers
var
A, B, C, D, E, F : Integer;

begin
A := 32;
B := StrToInt('100');    // '100' string converted to 100 integer
C := StrToInt('  -12');  // Leading blanks are ignored
D := StrToInt('\$1E');    // Hexadecimal values start with a '\$'
E := StrToInt('-0x1E');  // ... or with a '0x'
F := A + B + C + D + E;  // Lets add up all these integers

ShowMessage('A : '+IntToStr(A));
ShowMessage('B : '+IntToStr(B));
ShowMessage('C : '+IntToStr(C));
ShowMessage('D : '+IntToStr(D));
ShowMessage('E : '+IntToStr(E));
ShowMessage('F : '+IntToStr(F));
end;
Show full unit code
A : 32
B : 100
C : -12
D : 30
E : -30
F : 120

 Example code : Catching string to integer conversion errors var   A : Integer; begin   // We will catch conversion errors   try     A := StrToInt('100 ');    // Trailing blanks are not supported   except     on Exception : EConvertError do       ShowMessage(Exception.Message);   end;   try     A := StrToInt('\$FG');    // 'G' is an invalid hexadecimal digit   except     on Exception : EConvertError do       ShowMessage(Exception.Message);   end; end; Show full unit code '100 ' is not a valid integer value   '\$FG' is not a valid integer value