Overloading

[muhammad k]

Typically, the member functions of the Standard Library class string which take a string argument, are overloaded with both the parameter types const String& as well as const char*. Why is this so?
Also Given a class Complex, for complex numbers, which has a conversion from double, can we say that using two overloadings of the respective functions is worthwhile?

any help?

[gunnerfunner]

const String&

: copy ctor

as well as const char*

: from C-string
http://www.cplusplus.com/reference/string/string/string/

Given a class Complex, for complex numbers, which has a conversion from double, can we say that using two overloadings of the respective functions is worthwhile?

to prevent implicit conversions from double (d) to Complex (c = d + 0*i), even a Complex ctor with one argument should be qualified explicit:

#include <iostream>
using namespace std;

struct Complex
{
    double m_real;
    double m_imaginary;

    explicit Complex(double real): m_real (real), m_imaginary(0){};
};

int main()
{
    Complex c = 7;//error: conversion from 'int' to non-scalar type 'Complex' requested
		//but w/o explicit keyword this program would compile fine, copy intialization selects Complex::Complex(double)
}

http://en.cppreference.com/w/cpp/language/explicit

[muhammad k]

thank you for your reply but I am still not sure what you meant....I am sorry for my lack of understanding, can you please elaborate and explain in a bit more detail both part a and b?