Calling overloaded function with an array parameter and a non-array parameter

Question

I have this overloaded functions:

CString TestFunction(CString s, int number, int optPar1 = 123, int optPar2 = 456) //...
CString TestFunction(int index, CString s, int numbers[], int optPar1 = 123, int optPar2 = 456) //...
CString TestFunction(CString s, int numbers[], int optPar1 = 123, int optPar2 = 456) //...

When I do this:

1st case:

CString s = TestFunction(someString, anArrayOfIntsWithValues);

2nd case:

for (int i =0; i < max; i++)
{
    CString s = TestFunction(i, someString, anArrayOfIntsWithValues);
}

It gives me:

On the 1st case:

error C2664: 'CString Class1::TestFunction(CString, int, int, int)' : cannot convert parameter 2 from 'const int [2]' to 'int'
    5   IntelliSense: no instance of overloaded function "Class1::TestFunction" matches the argument list

On the 2nd case:

Error   2   error C2664: 'CString Class1::TestFunction(CString, int,int,int)' : cannot convert parameter 1 from 'int' to 'CString'
6   IntelliSense: no instance of overloaded function "Class1::TestFunction" matches the argument list

I am new to C++ and I don't know what is wrong with this code, but it was perfectly compiled in C# (with the knowledge of overloaded functions and optional parameters).

Note: this is just a representation of the real code - user-defined types are used as parameters.

EDIT: added a second case and 1st case was already answered.

Note that using [] in parameter list is archaic and actually the array is not passed by value . So this may differ from your expectations if you are coming from other languages — M.M
– M.M, Commented Jun 15, 2017 at 3:44

songyuanyao · Accepted Answer · 2017-06-15 04:03:29Z

2

At first, the parameter declaration int numbers[] is same as int* numbers in fact. Then,

anArrayOfIntsWithValues is an array of const int, i.e. const int[2]; which could decay to const int*, but can't be implicitly converted to both int and int*, then calling failed.

If you want the 2nd overload to be invoked, you can change the type of anArrayOfIntsWithValues to int [2], or change the type of parameter numbers to const int[] (or const int*), to make them match.

edited Jun 15, 2017 at 4:03

answered Jun 15, 2017 at 3:01

songyuanyao

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