How is ambiguity determined in the overload resolution algorithm?

Question

I\'m trying to understand the overloading resolution method.

Why is this ambiguous:

void func(double, int, int, double) {}
void func(int, double, double,         


        

Answer 1

Ambiguity is determined by the ranking:

1. Exact match: no conversion required, lvalue-to-rvalue conversion, qualification conversion, user-defined conversion of class type to the same class
2. Promotion: integral promotion, floating-point promotion
3. Conversion: integral conversion, floating-point conversion, floating-integral conversion, pointer conversion, pointer-to-member conversion, boolean conversion, user-defined conversion of a derived class to its base

Exact match wins vs Promotion which wins vs Conversion.

In the example:

void func(int, bool, float, int){cout << "int,bool,float,int" << endl;}
void func(int, bool, int, int){cout << "int,int,int,int" << endl;}

int main()
{
    func(1,1,3.4,4);
}

Argument 1(1) is an exact match on both
Argument 2(1) is an exact match on both
Argument 3(3.4) can be converted into float and int - Ambiguity Neither is better.
Argument 4(4) is an exact match on both

But if we did this: func(1,1,3.4f,4);
(3.4f) is now an exact match!
void func(int, bool, float, int) then wins the battle.