Defensive Looping

Defending The Loop

✅ Reasons to Replace or Unroll a for Loop

🔧 1. Dynamic Loop Control

Need to Skip or Break Midway Based on Complex Conditions)

Problem: for loops define the loop control in one place and expect it to change in a predictable pattern.

❌ for loop (gets messy):

for (int i = 0; i < 10; i++) {
    if (some_weird_condition(i)) { // while in come compilers, the i value can be changed when exiting the function, and in some it remembers by popping the stack
        i += 2; // Looks like it skips, but...
    }
    printf("%d\n", i);
}

/**
*  loop variable in a for loop behaves differently depending on whether:
1. The compiler optimizes it into a register, or
2. It’s updated after function calls or stack frames
*/

🧨 The Problem in C/C++: for Loop Hides the Real Control

❌ Why this is misleading:
You think you're increasing i by 2 to skip ahead. But at the end of the loop, the i++ still happens, so the manual i += 2 gets overridden or muddled.
Also, depending on optimization, i may be cached in a register, and modifying it may not reflect as expected if some_weird_condition exits early or changes context (like returning from a nested function).