Infinite loop when using size_t in a count down for loop

Question

So I'm using size_t instead of int in any indexing for loop to prevent negative indices. But when counting down, this leads to an overflow:

for (size_t i = 10; i >= 0; --i) {
    // Do something, f.ex. array[i] = i
}

What would be a nice way to prevent this?

• Using int instead?
• Using i == 0 as the termination condition? (This would however not work if I need the 0)

I'd appreciate any feedback!

Answer 1

for (size_t i = 10; i <= 10; --i) // do something

When overflow do happens, it will round to the largest integer and thus the condition will fail.

Answer 2

for (size_t i = 11; i-- > 0; ) {
    // Do something, f.ex. array[i] = i
}

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Note: The question starts the loop with value=10(which is strange, but not impossible). I start with 11, but the first time the loop body is enterered, it has already been decremented to 10.