CHAPTER 1: Getting Started

Exercises Section 1

Exercise 1.1: Review the documentation for your compiler and determine what file naming convention it uses. Compile and run the main program from page2.

• GCC and File Extensions
• File Types Created for Visual C++ Projects

Exercise 1.2: Change the program to return -1. A return value of -1 is often treated as an indicator that the program failed. Recompile and rerun your program to see how your system treats a failure indicator from main.

Windows

Linux

Exercise1.3 Write a program to print Hello, World on the standard output.

#include 
int main()
{
      std::cout << "Hello, World" << std::endl;
      return 0;
}

Exercise1.4 Our program used the addition operator, +, to add two numbers. Write a program that uses the multiplication operator, *, to print the product instead.

#include 

int main()
{
    std::cout << "Enter two numbers: " << std::endl;
    int v1 = 0, v2 = 0;
    std::cin >> v1 >> v2;
    std::cout << "The product is " << v1 * v2 << std::endl;

    return 0;
}

Exercise 1.5 We wrote the output in one large statement. Rewrite the program to use a separate statement to print each operand.

#include 

int main()
{
    std::cout << "Enter two numbers:" << std::endl;
    int v1 = 0, v2 = 0;
    std::cin >> v1 >> v2;
    std::cout << "The product of ";
    std::cout << v1;
    std::cout << " and ";
    std::cout << v2;
    std::cout << "is " << v1 * v2 << std::endl;

    return 0;
}

Exercise 1.6 Explain whether the following program fragment is legal

std::cout << "The sum of " << v1;
          << " and ";
          << " is " << v1 + v2 << std::endl;

If the program is legal, what does it do? If the program is not legal, why not? How would you fix it?

• Error: expected primay-expression befor '<<' token
• Fixed if: remove the spare semicolons;

    std::cout << "The sum of " 
    << v1 << " and " << v2 << " is " 
    << v1 + v2 << std::endl;

Exercise 1.7 Compile a program that has incorretly nested comments.

/*
* comment pairs /* */ cannot nest.
* ''cannot nest'' is considered source code,
* as is the rest of the program
*/
int main()
{
    return 0;
}

EX1.7

Exercise 1.8 Indicate which, if any, of the following output statements are legal:

std::cout << "/*";
std::cout << "*/";
std::cout << /* "*/" */;
std::cout << /* "*/" /* "/*" */;

After you've predicated what will happen, test your answers by compiling a program with each of these statements. Correct any errors you encounter.

• ...

Exercise 1.9 Write a program that uses a while to sum the numbers from 50 to 100.

#include 

using std::cin;
using std::cout;
using std::endl;

auto sum(int lo, int hi)
{
    int sum = 0;
    while(lo < hi)
        sum += lo++;
    return sum;
}

int main()
{
    cout << "sum is: " 
         << sum(50, 100+1) << endl;

    return 0;
}

Exercise 1.10 In addition to the ++ operator that adds 1 to its operand, there is a decrement operator(--) that subtracts 1. Use the decrement operator to write a while that prints the numbers from ten down to zero.

    #include 

using std::cin;
using std::cout;
using std::endl;

int main()
{
    int i = 10;
    while(i >= 0)
        std::out << i-- << " ";

    return 0;
}

Exercise 1.11 Write a program that prompts the user for two integers. Print each number in the range specified by those two integers.

    #include 

using std::cin;
using std::cout;
using std::endl;

void print_range(int lo, int hi)
{
    if (lo > hi)
    {
        print_range(hi, lo);
    }
    for (int i = lo; i != hi; ++i)
        cout << i << " ";
}

int main()
{
    int low = 0, high = 0;
    cout << "Please input two integers:\n";
    cin >> low >> high;
    print_range(low, high);
    return 0;
}