1.12 __ Chapter 1 comprehensive quiz

Question 1

Write a single-file program (named main.cpp) that reads two separate integers from the user, adds them together, and then outputs the answer. The program should use three functions:

• A function named “readNumber” should be used to get (and return) a single integer from the user.
• A function named “writeAnswer” should be used to output the answer. This function should take a single parameter and have no return value.
• A main() function should be used to glue the above functions together.

Hint: You do not need to write a separate function to do the adding (just use operator+ directly).
Hint: You will need to call readNumber() twice.
Hint: If you’re using visual studio with precompiled headers, don’t forget to #include “stdafx.h”.

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Question 2

Modify the program you wrote in exercise #1 so that readNumber and writeAnswer() live in a separate file called “io.cpp”. Use a forward declaration to access them from main().

Hint: If you’re having problems, make sure io.cpp is properly added to your project so it gets compiled (see lession 1.8 -- programs with multiple files for more information on how to do this).

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Question 3

Modify the program you wrote in #2 so that it uses a header file (named io.h) to access the functions instead of using forward declarations directly in your code (.cpp) files. Make sure your header file uses header guards.

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io.cpp:

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#include <iostream>   int readNumber() {     std::cout << "Enter a number: ";     int x;     std::cin >> x;     return x; }   void writeAnswer(int x) {     std::cout << "The answer is " << x << std::endl; }

io.h:

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#ifndef IO_H #define IO_H   int readNumber(); void writeAnswer(int x);   #endif

main.cpp:

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#include "io.h"   int main() {     int x = readNumber();     int y = readNumber();     writeAnswer(x+y);     return 0; }