5 replies to this topic

[espdev-darkness]

Hey guys, I was reading my C++ book when I came across the chapter on pointers. When I heard they point to the memory adress in which a variable is stored my heart lept for joy. You see Im very intrigued by the unexpected potentials of programming languages. If you look at the code below you will see my potential idea for a program that could crash a computer in a matter of seconds.

// Memory Re-write program


#include <iostream>


using namespace std;


int main()

{

	int initialAdress = 1;

	int* pointer = &initialAdress;


	while(true) // I have no intention of breaking this loop

	{

		pointer += 1;

		*pointer = 1337;

	}


               return 0;

}

Basicly what this program does is increase the actual memory adress that the pointer is pointing at by 1. I'm assuming this would give it a random memory adress. From here I assign that memory adress to the value 1 ( correct me if im not stating this properly). This continues forever, well until the computer crashes due to overwriting an important adress in memory. Please do not think Im some sort of script kiddie looking to crash computers, I'm not I just want to understand the language and its strange capabilities better.

[Guest]

You aren't going to crash anything. If a program tries to write memory that it isn't supposed to, the operating system will give a segmentation fault.

[Alexander]

What do you mean by strange capability? Do you understand C requires this low level access to do anything complex?

[WingedPanther]

I did something similar with BASIC in the old days of MS-DOS. It crashed the OS. Modern OS's do NOT let you do that, however.

[mebob]

You can't crash it because modern OS's run in something called "Protected Mode". Basically, when the OS is booting up, it makes a bunch of descriptors that tell the CPU what the memory limits for each program is, then loads this in to the processor. It's actually more complex than this, but this is a simple explanation.

[espdev-darkness]

Wow, thanks for all the help understanding this. This just goes to show how much I have to learn.