I realized I was freeing all the malloc’d space inside the for loops. That’s why my program was terminating after one row lol. God bless the debugger lol

Ok so I ran the code through the debugger and I think I’ve found the issue. Once the loop that reproduces the scanline rows by factor times finishes the job once, the program breaks out of that loop and finishes the code. There is no loop that comes back to the second row and starts the resizing process from the beginning. The bmp that I’m resizing is a green block with a white square in the middle. So this solution is reproducing the top line of the square (top row of just green pixels) correctly but then the program is filling the rest of the image with garbage values.

I’m guessing I need to put the whole process within an even bigger loop to resize the WHOLE image and not just the top line. What do you think?

Awesome!

We’re actually using the debugger from the CS50 IDE this year. Did you have this when you took the course? It makes everything so much easier. I’m going to start the python problem sets but once I check the pixel values I’ll def let you know! Thank you for being so responsive and supportive. You rock!

Happy to help! What happens when you run gdb? The pixel data structure should have some info as you step into the functions and check the value of the rgbs. Let me know how it goes. Always use GDB. It’s tough at first but gives you a huge amount of information as you examine pieces of your code as it executes in slow motion. Thanks for your comment!

Happy to help! Check out my blog posts that talk about debugging. What helped me the most was stepping through my program on instruction at a time. When you create a loop this is very helpful! Also do some simple tests using fread in an online REPL.