C++ How to Program, 10/e

2.5 Memory Concepts

Variable names such as number1, number2 and sum actually correspond to locations in the computer’s memory. Every variable has a name, a type, a size and a value.

In the addition program of Fig. 2.5, when the statement in line 13

std::cin >> number1; // read first integer from user into number1

is executed, the integer typed by the user is placed into a memory location to which the name number1 has been assigned by the compiler. Suppose the user enters 45 for number1. The computer will place 45 into the location number1, as shown in Fig. 2.6. When a value is placed in a memory location, the value overwrites the previous value in that location; thus, placing a new value into a memory location is said to be a destructive