In C++ a variable is a place to store information. A variable is a location in your computer’s memory in which you can store a value and from which you can later retrieve that value.

Your computer’s memory can be viewed as a series of cubbyholes. Each cubbyhole is one of many, many such holes all lined up. Each cubbyhole—or memory location—is numbered sequentially. These numbers are known as memory addresses. A variable reserves one or more cubbyholes in which you may store a value.

Your variable’s name (for example, myVariable) is a label on one of these cubbyholes, so that you can find it easily without knowing its actual memory address. Figure 3.1 is a schematic representation of this idea. As you can see from the figure, myVariable starts at memory address 103. Depending on the size of myVariable, it can take up one or more memory addresses.

Figure 3.1. A schematic representation of memory.

NOTE: RAM is random access memory. When you run your program, it is loaded into RAM from the disk file. All variables are also created in RAM. When programmers talk of memory, it is usually RAM to which they are referring.