Question

void foo(int,int) {}
void foo(int ,float) {}
void foo(float,int) {}

void main()
{
  unsigned int i = 10;
  unsigned float f = 1.0;       //line 5
  foo(i,f); // ambiguous call error
}

replacing line 5 by

float f = 1.0;

makes the program work. Why is it so?

I am working on visual studio 2005.

Answer 1

There is no such data type as unsigned float. Pay attention to compiler warnings; if you’re not getting any bump up the warning level. From running this example on Visual Studio 2010 it looks like the compiler ignores the float keyword in the declaration

unsigned float f = 1.0;

This makes f an unsigned int. Since you don’t have an overload of foo() that takes an int and unsigned int the compiler is unable to deduce which overload to call. If you add another overload

void foo(int,unsigned int) {}

the ambiguous call error disappears.