Submission Details
Severity:
[G-01] - Use `do-while` loop instead of `for-loop` to save users gas cost.
Details
do-while does not check the first condition and prevents the assembly from executing lots of opcodes needed for conditions checks and all these places are right for it because these all always execute the code inside loops on the first condition.
https://github.com/Cyfrin/2023-07-foundry-defi-stablecoin/blob/main/src/DSCEngine.sol#L118
Deployment Cost
| Calculation Type | Before | After | Gas Saved |
|---|---|---|---|
| Avg | 1004332 | 1004274 | 58 |
// For example ETH / USD, BTC / USD, MKR / USD, etc
- for (uint256 i = 0; i < tokenAddresses.length; i++) {
+ uint256 i;
+
+ do {
s_priceFeeds[tokenAddresses[i]] = priceFeedAddresses[i];
s_collateralTokens.push(tokenAddresses[i]);
- }
+ i++;
+ } while (i < tokenAddresses.length);
+
i_dsc = DecentralizedStableCoin(dscAddress);
https://github.com/Cyfrin/2023-07-foundry-defi-stablecoin/blob/main/src/DSCEngine.sol#L353-L357
| Calculation Type | Before | After | Gas Saved |
|---|---|---|---|
| Avg | 42356 | 42211 | 145 |
// the price, to get the USD value
- for (uint256 i = 0; i < s_collateralTokens.length; i++) {
+ uint256 i;
+ do {
address token = s_collateralTokens[i];
uint256 amount = s_collateralDeposited[user][token];
totalCollateralValueInUsd += getUsdValue(token, amount);
- }
+ i++;
+ } while (i < s_collateralTokens.length);
+
return totalCollateralValueInUsd;
Prize pool breakdown
Total prize
15,000 USDC
nSLOC
23664 USDC / LOC
14,000 USDC
1,000 USDC
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