Yashotantra Academy logo
← Solidity theorytheory 0/50 · 0%
level 1
Curious · 0 XP
streak
0d
perfect
0
badges
0

100 XP to Apprentice

Fundamentals · easy

11. Control flow

if, for, while, break and continue in a gas-metered world.

1 min read3 questionsup to 50 XPtopic 11/50

Read in another language

AI translates the explanation and quiz text while preserving code and answer scoring.

Control flow looks like C, but every iteration costs gas, so loops must be bounded by something the caller controls or by a constant.

solidity
for (uint256 i; i < xs.length; ++i) {
    if (xs[i] == 0) continue;
    total += xs[i];
}

Prefer `++i` over `i++` and cache `xs.length` in a local for a small saving on hot loops.

How to study this topic

  1. 1. Read the explanation once end to end, skipping the code.
  2. 2. Re-read the code snippets and say out loud what each line does.
  3. 3. Answer the quiz without scrolling back — that is the real check.
  4. 4. Read every explanation, even for the answers you got right.

Scoring

  • · Up to 30 XP from quiz accuracy.
  • · +15 XP for a perfect first attempt.
  • · +5 XP while a 3-day streak is running.
  • · 75% or higher marks the topic complete.

Check your understanding

  1. 1. Why must loops be bounded?

  2. 2. Which is marginally cheaper?

  3. 3. What does `continue` do?

Badges

First light
Pass your first topic
Sharp shooter
3 perfect first-try quizzes
On a roll
Study 3 days in a row
Week warrior
Study 7 days in a row
Grinder
Earn 500 XP
Deep diver
Earn 1500 XP