Question

What does this C program do, and how does it do it? http://ideone.com/s1maB

Answer 1

it does runtime error

Answer 2

don't you get same?

Answer 3

It's not a runtime error if you use in on your own computer.

Answer 4

IDEone yields a runtime error because the function writes an image to file.

Answer 5

ok, sorry for stupid question :/

Answer 6

This program has some errors:

1. unsigned int *d = (void*)data;

should be replaced with

unsigned int *d = (unsigned int*) data;

2. scale[i] = 1 / (1 + sqrt(i + 1));
scale_u[i] = scale[i] / sqrt(i + 1);

should be replaced with

scale[i] = 1 / (1 + sqrt((double)(i + 1)));
scale_u[i] = scale[i] / (sqrt((double)(i + 1)));

3. w = 1./sqrt(i);

should be replaced with

w = 1./sqrt((double)i);

Now the program will compile without any error or warning (I tested it on Visual Studio 2010 Professional).

Answer 7

Output is this: http://pastebin.com/pGMfzMZD

The program is generating garbage string.......

for further information. i will have to go through this program deeply......(My exams are going now, sorry)

Answer 8

It's not a garbage string; open it with an image viewer :-P

Answer 9

On gcc with -Wall and the other annoying stuff toggled on, it only gave me warnings for the unused argc and argv, and the attached image is output:

Answer 10

It looks funny though :( supposed to me... solid but with shadows all over it and not weird looking :( fix it.

Answer 11

with which image viewer it should be opened??

Answer 12

I don't know which one in particular, but I personally use irfanview: http://www.irfanview.com/

Answer 13

I'm not really familiar with that .pgm format it wrote though : http://netpbm.sourceforge.net/doc/pgm.html

Answer 14

better use Coly Photo Viewer