Please explain me ......... How it is working...?

Question

1.00/5 (4 votes)

See more:

#include <stdio.h>
#include <stdlib.h>
#include<conio.h>

int n = 0;

void foo() {
    void* x;
    printf("%d\n", ++n);
    if (n >= 100) {
        exit(0);
    }
    *((char**) (&x + 4)) -= 5;
}

int main() {
    foo();
    return 1;
}

What I have tried:

i have tried to understand but i did not get it. please explain me .

Posted 19-Dec-16 8:43am

Mr. Rishi kumar

Updated 19-Dec-16 23:12pm

Richard MacCutchan

v2

Add a Solution

Comments

Kornfeld Eliyahu Peter 19-Dec-16 15:16pm

How about using your debugger!?

[no name] 19-Dec-16 15:16pm

Which specific part of what line is it that you do not understand?

[no name] 19-Dec-16 21:13pm

It is NOT working. How have you "tried to understand"? Compile and run it if you can. Then break out the debugger.

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

CPallini · Answer 1 · 2016-12-19T09:35:00

Solution 1

As far as I can understand, the program is accessing unallocated memeory, since x is not initialized and it is very likely pointing to garbage. In other words it is flawed.

Posted 19-Dec-16 9:35am

CPallini

Comments

Kornfeld Eliyahu Peter 20-Dec-16 6:23am

Don't spoil the fun! :-)

Patrice T · Answer 2 · 2016-12-19T14:31:00

You should learn to use the debugger as soon as possible. Rather than guessing what your code is doing, It is time to see your code executing and ensuring that it does what you expect.

Debugger - Wikipedia, the free encyclopedia[^]
Mastering Debugging in Visual Studio 2010 - A Beginner's Guide[^]
The debugger is here to show you what your code is doing and your task is to compare with what it should do.
There is no magic in the debugger, it don't find bugs, it just help you to. When the code don't do what is expected, you are close to a bug.