dApp (分散型アプリ)
分散型ネットワーク上で動作するアプリ。
Operators: == (Equal), != (Not Equal), > (Greater), < (Less), && (AND), || (OR), ! (NOT). Structures: If, Else If, Else, Switch, Case, Ternary (?:). Optimization: Avoiding deeply nested 'if' trees, using Early Returns, and leveraging Branch Prediction.
graph LR
Center["dApp (分散型アプリ)"]:::main
Pre_smart_contract["smart-contract"]:::pre --> Center
click Pre_smart_contract "/terms/smart-contract"
Rel_ethereum["ethereum"]:::related -.-> Center
click Rel_ethereum "/terms/ethereum"
Rel_ipfs["ipfs"]:::related -.-> Center
click Rel_ipfs "/terms/ipfs"
Rel_metamask["metamask"]:::related -.-> Center
click Rel_metamask "/terms/metamask"
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classDef pre fill:#0f172a,stroke:#3b82f6,color:#94a3b8,rx:5,ry:5;
classDef child fill:#0f172a,stroke:#10b981,color:#94a3b8,rx:5,ry:5;
classDef related fill:#0f172a,stroke:#8b5cf6,stroke-dasharray: 5 5,color:#94a3b8,rx:5,ry:5;
linkStyle default stroke:#4b5563,stroke-width:2px;
🧒 5歳でもわかるように説明
Conditional [logic](/ja/terms/logic) is like a 'Choose Your Own Adventure' book. It says: 'IF it is raining, THEN take an umbrella. ELSE, leave it at home.' The computer constantly asks these 'Yes or No' questions to figure out what to do next.
🤓 Expert Deep Dive
At the hardware level, conditional logic is implemented using 'Branch Instructions'. Modern CPUs use 'Branch Prediction' to guess which path a conditional will take to keep the execution pipeline full; a 'Branch Misprediction' causes a significant performance penalty. In high-level languages, 'Short-circuit Evaluation' is a critical feature where, for example, in an 'A && B' expression, 'B' is never evaluated if 'A' is false. Developers aim to minimize 'Cyclomatic Complexity'—the number of linear independent paths through a code's source—because deeply nested conditionals make software difficult to test, debug, and maintain. In the context of Smart Contracts (Solidity), conditional logic is often used as a 'Guard' (via require or revert) to ensure transaction safety and prevent unauthorized access.