How to rotate an image by 180 degree clockwise and counterclockwise using C codes?

[Rohit Ramesh]

I need help in C program in order to rotate any image clockwise and anticlockwise.

I searched a lot on net but couldn't able to find any solution.

[newb16]

Does cw and ccw rotation differ in case of 180 degrees? Anyway, after you read the image from file and stored it in the array of pixels, swap appropriate pixels values for the whole array.

[donbock]

What is the format of the image?

[Rohit Ramesh]

image is in jpeg and size is 160*120. Please suggest me algorithm so that i can build some codes.. In image processing i am very new.

[jkmyoung]

As an opening, slow method, I suggest you first

Convert the jpg into a 160x120 set of pixels.
Rotate them accordingly, eg (i,j) -> (160-i, 120-j).
Convert the pixels, back into a jpg.

Once you've done this, you should be able to see a refinement in your method.