Question

How can i read content of a file which is not a simple text file in c/c++? For example, I want to read image file such as .jpg/.png/.bmp and see the value at certain index,to check what colour it is? or if I have a .exe/.rar/.zip and want to know what value is stored at different indices?
I am aware of c style reading file, which is

FILE *fp;

fp = fopen("example.txt","r"); /* open for reading */

char c;

c = getc(fp) ;

I want to know if i replace “example.txt” with “image.png” or so, will it works? will i get correct data?

Answer 1

You would need to open the file in binary mode. This allows you to read the bytes in a “raw” mode where they are unchanged from what was in the file.

However, determining the color of a particular pixel, etc. requires that you fully understand the meaning of the bytes in the file and how they are arranged for the file being read. This second requirement is much more difficult. You’ll need to do some research on the format of that file type in order to do that.