CODEWITHSUNDEEP
c++
James Allan
James Allan

Reputation: 313

default parameters in c++

Consider the following:

int foo(int x , int z = 0);
int foo(int x, int y , int z = 0);

If I call this function like so:

foo( 1 , 2);

How does the compiler know which one to use?

Upvotes: 5

Views: 152

Answers (4)

Rohit Vipin Mathews
Rohit Vipin Mathews

Reputation: 11787

Compiler will report Ambiguous function overload. As you cannot figure out which function will b called so does the compiler

Upvotes: 2

Parag
Parag

Reputation: 7946

That is a nice question. But it will not compile because of ambigious call to foo(). You can remove this ambiguity by using different datatypes in function signature.

For more detail about default parameter and function overloading see http://www.smart2help.com/e-books/ticpp-2nd-ed-vol-one/Chapter07.html

Upvotes: 4

Alok Save
Alok Save

Reputation: 206518

It won't and hence this example will not compile cleanly, it will give you an compilation error.
It will give you an ambiguous function call error.

Online Sample: 

int foo(int x , int z = 0){return 0;} 
int foo(int x, int y , int z = 0){return 10;}

int main()
{
    foo( 1 , 2); 
    return 0;
}

Output:

prog.cpp: In function ‘int main()’:
prog.cpp:6: error: call of overloaded ‘foo(int, int)’ is ambiguous
prog.cpp:1: note: candidates are: int foo(int, int)
prog.cpp:2: note: int foo(int, int, int)

Upvotes: 8

Luchian Grigore
Luchian Grigore

Reputation: 258568

It doesn't, that's why you get a compiler error.

Upvotes: 5

Related Questions