Learn to Program with C_ Learn to Program using the Popular C Programming Language ( PDFDrive )

5.5 Assignment Operators
Chapter 5 ■ Programs with Repetition Logic
So far, we have used the assignment operator = to assign the value of an expression to a variable,
as in the following:
c = a + b
The entire construct consisting of the variable = and the expression is referred to as an
assignment expression. When the expression is followed by a semicolon, it becomes an assignment
statement. The value of an assignment expression is simply the value assigned to the variable.
For example, if a is 15 and b is 20, then the assignment expression
c = a + b
assigns the value 35 to c. The value of the (entire) assignment expression is also 35.
Multiple assignments are possible, as in
a = b = c = 13
The operator = evaluates from right to left, so the above is equivalent to
a = (b = (c = 13))
The rightmost assignment is done first, followed by the one to the left, and so on.
C provides other assignment operators, of which += is the most widely used. In Program P5.3,
above, we used the statement
sum = sum + num;
to add the value of num to sum. This can be written more neatly using += as:
sum += num; //add num to sum
n += 3
To add 3 to n, we could write
which is the same as
n = n + 3
Other assignment operators include -=, *=, /=, and %=. If op represents any of +, -, *, /, or %, then
variable op= expression
is equivalent to
variable = variable op expression
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