8.11. Introduction to C++ Standard Library Class Template vector

We now introduce C++ Standard Library class template vector, which represents a more robust type of array featuring many additional capabilities. As you’ll see in later chapters, C-style pointer-based arrays (i.e., the type of arrays presented thus far) have great potential for errors. For example, as mentioned earlier, a program can easily “walk off” either end of an array, because Visual C++ does not check whether subscripts fall outside the range of an array. Two arrays cannot be meaningfully compared with equality operators or relational operators. As you’ll learn in Chapter 9, pointer variables (known more commonly as pointers) contain memory addresses as their values. Array names are simply pointers to where the arrays begin in memory, and, of course, two arrays will always be at different memory locations. When an array is passed to a general-purpose function designed to handle arrays of any size, the size of the array must be passed as an additional argument. Furthermore, one array cannot be assigned to another with the assignment operator(s)—array names are const pointers, and, as you’ll learn in Chapter 9, a constant pointer cannot be used on the left side of an assignment operator. These and other capabilities certainly seem like “naturals” for dealing with arrays, but Visual C++ does not provide such capabilities. However, the C++ Standard Library provides class template vector to allow programmers to create a more powerful and less error-prone alternative to arrays. In Chapter 12, we present the means to implement such array capabilities as those provided by vector. You’ll learn how to customize operators for use with your own classes (a technique known as operator overloading).