CHAPTER 18. ARRAYS CHAPTER 18. ARRAYS

Chapter 18

Arrays

An array is just a set of variables in memory that lie next to each other and that have the same type^1.

18.1 Simple example

#include <stdio.h>

int main()

{

int a[20];

int i;

for (i=0; i<20; i++)

a[i]=i*2;

for (i=0; i<20; i++)

printf ("a[%d]=%d\n", i, a[i]);

return 0;

};

18.1.1 x86

MSVC

Let’s compile:

Listing 18.1: MSVC 2008

_TEXT SEGMENT

_i$ = -84 ; size = 4

_a$ = -80 ; size = 80

_main PROC

push ebp

mov ebp, esp

sub esp, 84 ; 00000054H

mov DWORD PTR _i$[ebp], 0

jmp SHORT $LN6@main

$LN5@main:

mov eax, DWORD PTR _i$[ebp]

add eax, 1

mov DWORD PTR _i$[ebp], eax

$LN6@main:

cmp DWORD PTR _i$[ebp], 20 ; 00000014H

jge SHORT $LN4@main

mov ecx, DWORD PTR _i$[ebp]

shl ecx, 1

(^1) AKA (^2) “homogeneous container”