Simple Segmentation Fault Proglem

Question

    PNG * original;
    original->readFromFile("in.png");
    int width  = original->width(); 
    int height = original->height();

I'm getting a segmentation fault in this bit of code. What am I doing wrong?

Did you ever initialize `PNG* original`? Otherwise, dereferencing it will be undefined. — PC Luddite, Sep 04 '15 at 20:25
-1 'cause you really could have tryied a bit harder on that one. At least try to solve your problems before you ask for help. — Nelson Teixeira, Sep 04 '15 at 20:30

score 2 · Answer 1 · answered Sep 04 '15 at 20:28

2

You must allocate memory, because original it's just a pointer.

Like this:

PNG *original = new PNG();

answered Sep 04 '15 at 20:28

Sergio

score 1 · Answer 2 · answered Sep 04 '15 at 20:20

1

You are dereferencing original without first having assigned anything to it.

You declared it as a PNG * but did not assign an object instance to that pointer.

answered Sep 04 '15 at 20:20

Eric J.

score 0 · Answer 3 · answered Sep 04 '15 at 20:33

0

Perhaps you don't need to use a pointer

PNG original;
original.readFromFile("in.png");
int width  = original.width(); 
int height = original.height();

Despite what some newbies seem to think pointers are not obligatory.

answered Sep 04 '15 at 20:33

john

3 Answers3