C++ is a very flexible language when it comes to formatting and writing code. It is also a strongly typed language, meaning there are rules about declaring the types of variables, which you can use to your advantage by making the compiler help you write better code. In this section, we will cover how to format C++ code and rules on declaring and scoping variables.

Other than string literals, you have free usage of white space (spaces, tabs, newlines), and are able to use as much or as little as you like. C++ statements are delimited by semicolons, so in the following code there are three statements, which will compile and run:

    int i = 4; 
    i = i / 2; 
    std::cout << "The result...

Operators are used to compute a value from one or more operands. The following table groups all of the operators with equal precedence and lists their associativity. The higher in the table, the higher precedence of execution the operator has in an expression. If you have several operators in an expression, the compiler will perform the higher--precedence operators before the lower--precedence operators. If an expression contains operators of equal precedence, then the compiler will use the associativity to decide whether an operand is grouped with the operator to its left or right.

C++ provides many ways to test values and loop through code.

The most frequently used conditional statement is if. In its simplest form, the if statement takes a logical expression in a pair of parentheses and is immediately followed by the statement that is executed if the condition is true:

    int i; 
    std::cin >> i; 
    if (i > 10) std::cout << "much too high!" << std::endl;

You can also use the else statement to catch occasions when the condition is false:

    int i; 
    std::cin >> i; 
    if (i > 10) std::cout << "much too high!" << std::endl; 
    else        std::cout << "within range&quot...

Let's now use the features you have learned in this chapter to write an application. This example is a simple command-line calculator; you type an expression such as 6 * 7, and the application parses the input and performs the calculation.

Start Visual C++ and click the File menu, and then New, and finally, click on the File... option to get the New File dialog. In the left-hand pane, click on Visual C++, and in the middle pane, click on C++ File (.cpp), and then click on the Open button. Before you do anything else, save this file. Using a Visual C++ console (a command line, which has the Visual C++ environment), navigate to the Beginning_C++ folder you created in the previous chapter and create a new folder called Chapter_02. Now, in Visual C++, on the File menu, click Save Source1.cpp As... and in the Save File As dialog locate the Chapter_02...

In this chapter, you have learned how to format your code, and how to identify expressions and statements. You have learned how to identify the scope of variables, and how to group collections of functions and variables into namespaces so that you can prevent name clashes. You have also learned the basic plumbing in C++ of looping and branching code, and how the built-in operators work. Finally, you put all of this together in a simple application that allows you to perform simple calculations at the command line.

In the following chapter, you will learn about C++ types and how to convert values from one type to another.