c++ - Strange ambiguous call to overloaded function error

Question

I'm trying

void function(int y,int w)
{
    printf("int function");

}


void function(float y,float w)
{
    printf("float function");
}


int main()
{
    function(1.2,2.2);
    return 0;
}

I get an error error like..

error C2668: 'function' : ambiguous call to overloaded function

and when I try to call function(1.2,2) or function(1,2.2) it is printing as "int function"

Please clarify when will the function(float y,float w) be called?

question from:https://stackoverflow.com/questions/16602175/strange-ambiguous-call-to-overloaded-function-error

Answer 1

Look at the error message from gcc:

a.cpp:16: error: call of overloaded ‘function(double, double)’ is ambiguous
a.cpp:3: note: candidates are: void function(int, int)
a.cpp:9: note:                 void function(float, float)

A call to either function would require truncation, which is why neither is preferred over the other. I suspect you really want void function(double y,double w). Remember that in C/C++, the default floating-point type for literals and parameter passing is double, NOT float.

UPDATE

If you really don't want to change the function signature from float to double, you can always use literals that are typed as float. If you add the suffix f to the floating point numbers, they will be typed float.

Your examples would then be function(1.2f, 2f) and function(1, 2.2f).