C ++中函数重载的困惑

Question

My program has two print functions: one for int and one for float .

void print(float a){
    cout << "float:" << a << endl;
}

void print(int a){
    cout << "integer:" << a << endl;
}

Whenever I call print(10) or print(0) the one for int datatype is called. But when I try to call print(3.5) , it gives compilation error. Why is it so?

PS when I have only one print function void print(float a) then print(3.5) works fine.

Answer 1

Note that 3.5 is a double , not a float . And it could be converted to both float and int implicitly, the invoking becomes ambiguous ( float with int ).

See floating point literal .

suffix, if present, is one of f , F , l , or L . The suffix determines the type of the floating-point literal:

  (no suffix) defines double f F defines float l L defines long double 

So you can call it by print(3.5f); to avoid ambiguity.

BTW: double could be converted to float implicitly, that's why if you have only one function then it works well.