string to integer conversion in Pascal, How to do it?

Question

How to convert a number printed in a string into integer?

Thank you.

Answer 1

The is procedure Val:

procedure Val(S; var V; var Code: Integer);

This procedure operate on decimal and real numbers.

Parmeters:

• S char sequence; for proper conversion it has to contain ‘+’, ‘-‘, ‘,’, ’.’, ’0’..’9’.
• V The result of conversion. If result going to be an Integer then S can't contain ‘,’, ’.’.
• C Return the position of the character from S, that interrupt the conversion.

Use cases:

Var Value :Integer;

Val('1234', Value, Code);  // Value = 1234, Code = 0
Val('1.234', Value, Code); // Value = 0, Code = 2
Val('abcd', Value, Code);  // Value = 0, Code = 1

Answer 2

You can use Val function.

Example:

var
   sNum: String;
   iNum: Integer;
   code: Integer;

begin
   s := '101';
   Val(s, iNum, code); 
end.

Answer 3

You want Val().