Solvequill Blog · coding · 4 min read · 1 views
Debug loops by writing the state, not by staring
A small table for finding off-by-one mistakes and wrong updates in loops.
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Loop bugs often feel invisible because your eyes read the code the way you intended it, not the way it runs.
The main idea
Track the variables that change on each iteration. Stop after three or four rows and compare the table with the expected pattern.
A short example
For a counter loop, write `i`, the condition result, and the value changed inside the loop.
1total = 02for i in range(1, 4):3 total += i4print(total)Check while you solve
- Write the first value before the loop body runs.
- Check whether the end value is included.
- Track only variables that can change.
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