CODEWITHSUNDEEP
c++functionc++11overloading
A. Khaled
A. Khaled

Reputation: 175

error when trying to run an overloaded function with float parameters.

I am trying to create a simple (absolute) function in c++, I have created two functions with the same name one that takes an integer and returns an integer and one that takes a float and returns a float but every time I try to run the code I receive this error:

"error: call of overloaded 'absolute(double)' is ambiguous"

I tried changing the input parameters of the second function so that it takes a double and returns a float and the code ran perfectly, I'd like to know why the code won't run when the parameters and return type are both set to float, thank you.

#include <iostream>
#include <fstream>

using namespace std;

int absolute(int x){
if (x<0){
    x=-x;
}
    return x;
}
float absolute (float x)
{
    if (x<0){
        x=-x;
    }
    return x;
}





int main( )
{
    cout << absolute(3.5);

}

Upvotes: 0

Views: 300

Answers (3)

Adnan
Adnan

Reputation: 23

you write that 3.5 is a float this value is not a float it is a double.

Upvotes: 1

R Sahu
R Sahu

Reputation: 206577

The type of the literal 3.5 is double, not float.

Choosing either of the overloads would require a conversion. Hence the ambiguity.

You can use 3.5f to make it a float literal.

cout << absolute(3.5f);

A better solution, IMO, would be to use a function template.

template <typename T>
T absolute(T x)
{
   return (x < 0 ? -x : x);
}

Upvotes: 3

Some programmer dude
Some programmer dude

Reputation: 409166

Read that error message again. Notice how it says double as the argument type it want to use.

That's because floating point constants like 3.5 are of type double. And the compiler don't know if it should convert the double value to an int or a float, thereby giving you the error.

If you want to call the float overload, use 3.5f to make it a float value. Or change your overload to use type double instead of float.

Upvotes: 1

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