C++ Logical Operators in Action: Complex Conditions in if Statements

This article introduces the practical application of logical operators in C++ if statements, with the following core content: Logical operators combine boolean conditions. C++ provides three: `&&` (logical AND, true only if both sides are true), `||` (logical OR, true if at least one side is true), and `!` (logical NOT, negation). Their precedence is `!` > `&&` > `||`, so parentheses are needed to clarify order in complex conditions. Practical scenarios: ① Range judgment (e.g., between 10-20: `num >= 10 && num <= 20`); ② OR conditions (e.g., score ≥ 90 or full attendance: `score >= 90 || attendance`); ③ Negation (non-negative numbers: `!(num < 0)`); ④ Nested conditions (e.g., age ≥ 18 and score ≥ 60, or age ≥ 20). Common errors: Misusing bitwise operator `&` instead of `&&`, ignoring short-circuit evaluation (e.g., `a > 0 && ++b > 0` where a = 0 prevents b from incrementing), and missing parentheses causing incorrect precedence (e.g., `a || b && c` should evaluate `b && c` first). Key takeaways: Master operator precedence, short-circuit特性, and parentheses usage.