How is the best match determined in C++ function overloading?

The order in which the best match is determined is: precision match standard conversion user-defined conversion default number of arguments minimum

The best match in C function overloading is How was it decided?

In C, function overloading allows you to create multiple versions of a function with the same name but different parameters. The compiler follows a set of rules to determine the best match when using the appropriate overloaded version.

Rules:

1. Precision matching: This rule applies when the actual participant number exactly matches the type of the formal participant number.
2. Standard conversion: This rule applies if an actual participant number can be implicitly converted to a formal participant number.
3. User-defined conversion: This rule applies if there is a user-defined conversion operator and the actual participants can be converted to formal participants.
4. Default parameters: Overloaded versions with default parameters have lower priority than versions without default parameters.

The order in which the best match is determined:

1. First, the compiler attempts an accuracy match.
2. If there is no precision match, the compiler will try to use standard conversion.
3. If there is no standard conversion, the compiler will try to use a user-defined conversion.
4. If no transformation applies, the compiler chooses the version with the fewest default parameters.

Practical case:

Consider the following code:

void foo(int x);
void foo(float x);

When calling foo(3.14), compile The compiler will use void foo(float x) as the best match because floating point constants 3.14 can be implicitly converted to the float type.

Additional Notes:

• The compiler will report an error if there are multiple overloaded versions with the same best match.
• The compiler will also report an error if it cannot determine the best match.
• To avoid ambiguity, it is best to ensure that the signatures of function overloads are distinct.

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