C interprets a value as a condition: zero means false, while any value different from zero means true. This applies to scalar types, including numerical types and pointers. Use a truth value directly rather than redundantly comparing it with 0, false, or true. section 3.1
Use a value directly as a condition
The conditions if (i != 0) and if (i) have the same logical effect. The shorter form exposes C's truth-value rule; !i negates that interpretation. The bool type stores false and true, represented technically by 0 and 1. section 3.1
Logical operators consume truth interpretations. ! negates its operand, while && and || produce false or true. Applying !! to a value converts it explicitly to a normalized truth value, allowing it to serve as an index. section 4.4.2
// This never divides by 0.
if (b != 0 && ((a/b) > 1)) {
++x;
}
Short-circuit evaluation makes the second operand unnecessary when the first operand determines the result; here, b must be nonzero before division occurs. section 4.4.2
