sirisampada.vinod2010

 Profile Answers by sirisampada.vinod2010 

• Mar 29th, 2009

 

When calling another function with parameters if you not give any parameter to that function then it will take an value which is already assigned.

dipuprits

 Profile Answers by dipuprits 

• Apr 14th, 2009

 

Default parameter is a default value for a parameter to a function.
 
The default value can be provided to the list of parameters starting from the right end. Ex: for a function fun(int i, float f, long l), you can specify default value as fun( int i, float f, long l = 1000) but not fun( int i = 10, float f, long l).

You can specify default value for overloaded function provided it is still different from the other forms when the default value is applied.

Ex: void Fun( int i );
void Fun( int i, int j, float f);
void Fun( int i, int j = 10);   // Ambiguous call.

the third version is not allowed as the compiler cannot decided which of the two to use when there is a call to this function like Fun(10) since it could either be Fun(10) or Fun(10,10).

amarnathsatrawala

 Profile Answers by amarnathsatrawala 

• Jun 16th, 2009

 

The overloads may not always be banned. The compiler could remove the parameter with default values for the overload resolution. e.g. The signature of the fuction after removing the default parameters should not match any other fuction signature.

Moreover the definition, may be still be allowed if there is no ambiguous call. The overload resolution may require help from the coder in that circumstance.

yzesong

 Profile Answers by yzesong 

• Jul 29th, 2009

 

This is my answer, please correct me if I am wrong.

Overloading functions with default parameters will cause compile error for ambiguous calling on the overloaded function.  But it really depends on the signatures of the overloaded function. If you don't call the overloaded function, as long as the signatures are different, it compiles fine. When you call them, you can not omit all the parameters because of ambiguity issue. 

Here is an example I played with, 

void PrintValues(int nValue1=10, int nValue2=20, int nValue3=30)

{

using namespace std;

cout << "IValues: " << nValue1 << " " << nValue2 << " " << nValue3 << endl;

}

double PrintValues(double fValue1= 1.1, double fValue2=2.2, double fValue3=3.3)

{

using namespace std;

cout << "FValues: " << fValue1 << " " << fValue2 << " " << fValue3 << endl;

return 99.9;

}

int main(int argc, char* argv[])

{

PrintValues(1, 2, 3);

PrintValues(1, 2);

PrintValues(1);

//PrintValues();  // this will causing ambiguity

PrintValues(88.88); // this is fine

return 0;

}

So generally, you don't want to do this.