Quick start manual

5-4

Delphi Language Guide

Simple types

Integer types

An integer type represents a subset of the whole numbers. The generic integer types

are Integer and Cardinal; use these whenever possible, since they result in the best

performance for the underlying CPU and operating system. The table below gives

their ranges and storage formats for the current 32-bit Delphi compiler.

Fundamental integer types include Shortint, Smallint, Longint, Int64, Byte, Word, and

Longword.

In general, arithmetic operations on integers return a value of type Integer—which, in

its current implementation, is equivalent to the 32-bit Longint. Operations return a

value of type Int64 only when performed on one or more Int64 operand. Hence the

following code produces incorrect results.

var

I: Integer;

J: Int64;

I := High(Integer);

J := I + 1;

To get an Int64 return value in this situation, cast I as Int64:

J := Int64(I) + 1;

For more information, see “Arithmetic operators” on page 4-7.

Note

Some standard routines that take integer arguments truncate Int64 values to 32 bits.

However, the High, Low, Succ, Pred, Inc, Dec, IntToStr, and IntToHex routines fully

support Int64 arguments. Also, the Round, Trunc, StrToInt64, and StrToInt64Def

functions return Int64 values. A few routines cannot take Int64 values at all.

Table 5.1 Generic integer types for 32-bit implementations of Delphi

Type Range Format

Integer –2147483648..2147483647 signed 32-bit

Cardinal 0..4294967295 unsigned 32-bit

Table 5.2 Fundamental integer types

Type Range Format

Shortint –128..127 signed 8-bit

Smallint –32768..32767 signed 16-bit

Longint –2147483648..2147483647 signed 32-bit

Int64 –2

..2

–1 signed 64-bit

Byte 0..255 unsigned 8-bit

Word 0..65535 unsigned 16-bit

Longword 0..4294967295 unsigned 32-bit