What are the differences, if any, between (type)value and type(value) in C casting?

Understanding the Nuances of (type)value and type(value) in C

In C , two different syntaxes exist for explicit type casting: (type)value and type(value). This distinction raises the question: what are the differences, if any, between these two expressions?

No Difference in Simple Casting

According to the C standard (section 5.2.3), when a simple type specifier is followed by a single expression enclosed in parentheses, the resulting expression creates a value of the specified type from the given expression.

Equivalence of (type)value and type(value)

For a single expression, (type)value is equivalent to type(value) in both definition and meaning. This means that there is absolutely no difference between these two expressions when casting a single value to a specified type.

Difference with Multiple Values

However, a subtle difference arises when casting a comma-separated list of values. In this case, if the specified type is a class with a suitably declared constructor, then type(x1, x2, ...) is equivalent to creating a temporary variable t of type T with the given values and assigning the value of t to the expression.

Type Name Restrictions

As an additional note, there are certain type names for which the type(value) syntax cannot be used. For instance, while (char )string is valid, char (string) will fail compilation. However, if the type is aliased using typedef, the type(value) syntax can be used with the alias name.

The above is the detailed content of What are the differences, if any, between (type)value and type(value) in C casting?. For more information, please follow other related articles on the PHP Chinese website!