What is a “cache-friendly” code?

Question

What is the difference between \"cache unfriendly code\" and the \"cache friendly\" code?

How can I make sure I write cache-efficie

Answer 1

Be aware that caches do not just cache continuous memory. They have multiple lines (at least 4) so discontinous and overlapping memory can often be stored just as efficiently.

What is missing from all the above examples is measured benchmarks. There are many myths about performance. Unless you measure it you do not know. Do not complicate your code unless you have a measured improvement.