Exam 4: Parameters and Overloading

Write a stub for the following function prototype: double root( double a,double b,double c,int i); // Precondition: a != 0 and a,b,c are coefficients of // a quadratic equation a*x*x + b*x + c = 0 The value // of i is either +1 or -1 to choose which root. // Postcondition: return value,x,satisfies the // equation a*x*x + b*x + c = 0

There is only one kind of parameter passing in C++,namely call-by-value. Explain.

A call-by-reference parameter may pass data only out of a function.

What does the function given here do when called if both the ampersands (&)are removed? Why? void func(int& x,int& y) { int t = x; x = y; y = t; }

Write a stub for the function whose declaration is given below.Do not write a program that calls this,just write the stub. Hint: This is very short. double yield (double pressure, double density,double temp); // Precondition: pressure is newtons per square meter // density is in kilograms per cubic meter // temp is in degrees Celcius // Postcondition: Return value is the relative yield of // a chemical process.It is a number between 0 and 1. // 0 means no output and 1 means ideal yield.

The compiler ha no problem distinguishing these two function definitions: void func(double &x){/*…*/} void func(double x){/*…*/}

There is no problem with these two function definitions: void func(int x){/*…*/} int func(double x){/*…*/ return something_double;}

Which of the following overloadings will be invoked by this call? g(1.0,2.0);

Given the function,and the main function calling it: What is the output of the following code if you omit the ampersand (&)from the first parameter,but not from the second parameter? (You are to assume this code is embedded in a correct function that calls it. ): #include <iostream> Using namespace std; Void func(int & x,int & y) { Int t = x; X = y; Y = t; } Int main() { Int u = 3;v = 4; // ).. Cout << u << " " << v << endl; Func ( u,v ) Cout << u << " " << v << endl; // ).. }

Carefully describe the call-by-value mechanism.

What is a stub?

The position of the ampersand in the function header is of no importance to the proper compiling and execution of code that uses call-by-reference parameters.

Define function signature:

Suppose a programmer supplies the ampersand for call-by-reference in a prototype,but forgets to put the ampersand in the definition.The compiler will nevertheless correctly interpret the programmer's intent and compile the function.

Write a void function definition for a function called zeroBoth that has two call-by-reference parameters,both of which are variables of type int,and that sets the values of both variables to 0.

The call-by-reference mechanism is specified in the function declaration and definition,using a $ between the type and the parameter.

A call-by-value parameter may pass data only into a function.

Functions that call other functions can be tested independently of the called functions.

Which of the following function declarations with default arguments are correct?

Consider the revised pizza buying program of Display 4.7.This program provides the following overloading for unitPrice functions for round and rectangular pizza: double unitPrice(int diameter,double price); double unitPrice(int length,int width,double price); Suppose we are faced with the need for the unit price on a square pizza.The problem here is to devise in a 'natural' way to overload unitPrice to compute the price per square inch of a square as well as a round pizza?