I think on a 64 bit memory when we declare a variable to be of type char or int, it actually uses all the 64 bits, except that it uses less than that. Correct?

However char will take one byte

UNLESS it is padded

padding does not change the type of the char

but thats because gcc is bad

can you proof that not using the full register is benefical?

mov rax, 0 encodes in 1+8 bytes mov al, 0 encodes in 1+1 byte

show me some scientifical proof.

How this does affect perf or whatever

Not on my pc so shrug

binary sizes are part of perf

then show it to me later or another day

show me an example where this matters

Have you ever endured the pain of downloading a computer game for five hours

I meant that on a 8 bytes memory, when we declare a char variable, it uses only one byte, and for example if we declare another char, it won't take the address of the next byte adjusting to the previous char, it has to take the beginning address of another row of 8 bytes. Correct?

you have no guarantee about hoe much it uses

I meant that on a 8 bytes memory, when we declare a char variable, it uses only one byte, and for example if we declare another char, it won't take the address of the next byte adjusting to the previous char, it has to take the beginning address of another row of 8 bytes. Correct?

I meant that on a 8 bytes memory, when we declare a char variable, it uses only one byte, and for example if we declare another char, it won't take the address of the next byte adjusting to the previous char, it has to take the beginning address of another row of 8 bytes. Correct?

this is completely up to the compiler.

How big was the game? How much was executable code?

Suppose it uses 1 bytes

Compiler specific struct Foo { char a; char b; }; this is likely to not contain padding. struct Foo { char a; int b; }; this is likely to contain 3 Bytes padding (between char and int). Since on this platform int is 4 Bytes and alignment is on 4 Bytes

Isnt padding word based on most ccs?

ccs?

Why wont the first example contain padding?

again - it depends, but why should it?

(char char) (int )

would pad

no guarantee though

that's why there is the 2nd example

But it might be important to show that padding can occur on a non struct level

well basically padding can occur everywhere except the beginning of the structure

A cell on memery contains how many of bytes?

No specifically cell

what's wrong with printf? it doesn't recognize it?

should be lower case p