BASIC ELEMENTS OF JAVA - Java Programming: From Problem Analysis to Program Design - page 54

TABLE 2-4 Values of the Variables num1 , num2 , and num3

Values of the
Variables

Variables Statement/Explanation

num1 num2 num3

Before
Statement 1

? ? ?

num1 num2 num3 num1 = 18;

Store 18 into num1 .

After
Statement 1

18 ? ?

num1 = num1 + 27;

num1 num2 num3

After
Statement 2

num1 + 27 = 18 + 27 = 45.
This value is assigned to
num1 , which replaces the
old value of num1 .

45 ? ?

num2 = num1;

num1 num2 num3

After
Statement 3

Copy the value of num1
into num2 .

45 45 ?

num3 = num2 / 5;

num1 num2 num3

After
Statement 4

45 45 9 num2 / 5 = 45 / 5 = 9.

This value is assigned to
num3 .So num3 = 9 .

num3 = num3 / 4;

num1 num2 num3

After
Statement 5

num3 / 4 = 9 / 4 = 2.
This value is assigned to
num3 , which replaces the
old value of num3 .

45 45 2

Thus, after the execution of the statement in Line 5, num1 = 45 , num2 = 45 ,and num3 = 2 .

The Java language is strongly typed, which means that you cannot assign a value
to a variable that is not compatible with its data type. For example, a string cannot
be stored in an int variable. If you try to store an incompatible value in a variable,
an error is generated when you compile the program or during program execution.
Therefore, in an assignment statement, the expression on the right side must evaluate
to a value compatible with the data type of the variable on the left side.