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I have numbers;

A == 0x20000000
B == 18
C == (B/10)
D == 0x20000004 == (A + C)

A and D are in hex, but I'm not sure what the assumed numeric bases of the others are (although I'd assume base 10 since they don't explicitly state a base.

It may or may not be relevant but I'm dealing with memory addresses, A and D are pointers.

The part I'm failing to understand is how 18/10 gives me 0x4.

Edit: Code for clarity:

*address1 (pointer is to address: 0x20000000)

printf("Test1: %p\n", address1);
printf("Test2: %p\n", address1+(18/10));
printf("Test3: %p\n", address1+(21/10));

Output:

Test1: 0x20000000
Test2: 0x20000004
Test3: 0x20000008
Hamid
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1 Answers1

9

Notice some facts:

1) when you add a value to the address it gets increased by that value multiplied by the number of bytes contained in a word, not by simply that value;

2) 18/10 == 1 when it comes to integers;

3) 21/10 == 2 when it comes to integers;

4) word size is 4 in this case (as you notice by the pointer's size, being 32 bit);

Consequently:

0x20000000 + 4 * (18/10) = 0x20000000 + 4 * 1 = 0x20000004
0x20000000 + 4 * (21/10) = 0x20000000 + 4 * 2 = 0x20000008

Edit:
As Vatine pointed out, it's important understanding that the pointer is incremented by a value multiplied by 4 (i.e a word's size in a 32-bit system) because that's the size of the data type the pointer variable was created for (an int).

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Nadir Sampaoli
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