Skip to main content Link Menu Expand (external link) Document Search Copy Copied

Function overloading quiz

What is the output of the following code?

import std.uni : toLower;

int fun(string s)
in (s == s.toLower())
{
    return -42;
}

string fun(int x)
out (; x >= 0)
{
    x *= -42;
    return "Hello World!";
}

void main()
{
    import std.stdio : writeln;

    writeln(fun("hello world!"));
    writeln(fun(-42));
}
Question

What is the output for the snippet above?

Runtime error at 1st call of fun()

The call fun('hello world!') will trigger our first function(that takes as input a string). It respects the in contract so it will just return -42. The second call fun(-42) will trigger the second function. At the end of the function the value of x will be -42 * -42, it respects the out contract, so it will return ‘Hello World!’

Runtime error at 2nd call of fun()

The call fun('hello world!') will trigger our first function(that takes as input a string). It respects the in contract so it will just return -42. The second call fun(-42) will trigger the second function. At the end of the function the value of x will be -42 * -42, it respects the out contract, so it will return ‘Hello World!’

hello world!

The call fun('hello world!') will trigger our first function(that takes as input a string). It respects the in contract so it will just return -42. The second call fun(-42) will trigger the second function. At the end of the function the value of x will be -42 * -42, it respects the out contract, so it will return ‘Hello World!’

-42

The call fun('hello world!') will trigger our first function(that takes as input a string). It respects the in contract so it will just return -42. The second call fun(-42) will trigger the second function. At the end of the function the value of x will be -42 * -42, it respects the out contract, so it will return ‘Hello World!’

-42 Hello World!

Correct!