4. Variables
X Becomes X Plus 3
Let us now try something a little "scarier":
double x = 4; x = x+3;
What is the value of x? Does the
second statement even make sense? It does if we understand the
symbol '=' denotes the operation of assignment in C++. To perform the
assignment, the value on its right needs to be calculated first.
The value of variable x is set to
4 as the consequence of the first statement. The second statement first makes
us evaluate the value on the right side of the assignment. Since x equals 4
at that moment, the expression x+3 evaluates to value 7. This value
is then assigned to variable x. Thus, the second statement set value of
variable x to 7. In other words, the second statement increases the value of variable x by 3.