Quick C Question

I have a C homework to do (I am a C++ guy) and the question asks us how to fix the following code the crashes:

int *a = 0;
*a = 5;

Fix it using dynamic memory management or static variables.

Now I have written programs that are 10,000 times longer. I am lost at what they are trying to do with the given code. So please help!

The code is attempting to store the value 5 into the variable a.

That should be enough for someone who has "written programs that are 10,000 times longer" ;).

OK, I thought that for a second...i just sure as heck hope thats what my teacher is trying to show. It's simply two lines of retarded code...at least to make a mistake like that. So...I was just making sure...thanks!

>(I am a C++ guy)
Those two lines are C++ code too. But if you never studied pointers in C++, you wouldn't know what they do.

Tbh, I have always known pointers from when I learned them, but via school we have always used Java, so I haven't worked that much with pointers. I used an array to fix the code, but I was not sure how dynamic memory management played into the code, but I found static code that worked.

To make the code not crash was not hard, but to make the code do what the person who wrote it wanted needed that answer from Kennedy, so thanks!

Quote:

---

Originally Posted by vgame64

I have a C homework to do (I am a C++ guy) and the question asks us how to fix the following code the crashes:

int *a = 0;
*a = 5;

Fix it using dynamic memory management or static variables.

---

To clarify the issue, for people who have not written programs 10000 times longer:

The reason the code is incorrect is because the pointer doesn't point to anything specific. That's bad. Make it point to a variable first.


Quzah.

>Tbh, I have always known pointers from when I learned them
Admittedly, pointers aren't used that much in modern C++ anymore. They are used behind the scenes of course, but using vectors, strings, and such, you don't need to be concerned with them unless you're doing something fancy.

Mmmm, 10K lines of C++ without a single pointer?

"For the millionth time, stop exaggerating!"

A bit off topic, but you must always initalize your pointers, if you do not have a variable to assign the pointer to, please always assign it to NULL. This is one of the safest things you can do in C,C++ programming, as a dangling or lost pointer is pointing to an unknown part of computer memory which is very dangerous

The code should be

Code:

---

int *a = malloc(sizeof(int)); /*malloc() allocates required memory for one int and returns its address*/
*a = 5;

---

Code:

---

static int b = 0;
int *a = &b;
*a = 5;
printf("b=%d\n", *a);

---