Programming C increment and decrement

1. Increment and Decrement Operators
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2. Increment Operator (++)
● The increment operator (++) adds 1 to its operand.
● It is an unary operator
( A operator that requires only one operand is known as
unary operator )
● Auto-increment
● i++ add 1 to i
● i = i + 1 can be represented in two forms as
1) i += 1 2) i++
● k = 2 * i++
( means ``take i's old value and multiply it by 2, increment i,
store the result of the multiplication in k'' )
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3. Decrement Operator (--)
● The decrement operator (++) subtract 1 from its
operand.
● It is an unary operator
( A operator that requires only one operand is known as
unary operator )
● Auto-decrement
● i-- subtracts 1 from i
● i = i - 1 can be represented in two forms as
1) I -= 1 2) i--
● k = 2 * i--
( means ``take i's old value and multiply it by 2, decrement i,
store the result of the multiplication in k'' )
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4. Postfix and Prefix Forms
● There are two forms for each of the operators:
postfix and prefix
● The statement ++i (prefix form) increments i
before using its value
● The statement i++ (postfix form) increments it
after its value has been used.
● The postfix increment and decrement
operators fetch the current value of the
variable
● Store a copy of it in a temporary location. The
compiler then increments or decrements the
variable
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5. Postfix Forms - Example
● i = 5;
j = i++;
printf(“nj : %d and i : %d”, j, i);
● Output :
j : 5 and I : 6
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6. Postfix Forms - Example
● i = 5;
j = i++;
printf(“nj : %d and i : %d”, j, i);
printf(“ni : %d”,i++);
printf(“ni : %d”,i);
● Output :
j : 5 and i : 6
i:6
i:7
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7. Prefix Forms - Example
● i = 5;
j = ++i;
printf(“nj : %d and i : %d”, j, i);
● Output :
j : 6 and i : 6
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8. Prefix Forms - Example
● i = 5;
j = ++i;
printf(“nj : %d and i : %d”, j, i);
printf(“ni : %d”,++i);
printf(“ni : %d”,i);
● Output :
j : 6 and i : 6
i:7
i:7
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9. Precedence of Increment and
Decrement Operators
● The increment and decrement operators have
the same precedence, but bind from right to
left. So the expression
● --j++
s evaluated as
--(j++)
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10. Precedence of Increment and
Decrement Operators -
Examples the value of k in i then
● i=k--; /* Stores
decrements k. */
● J=i++; /* Stores the value of l in j then
increments i. */
● i=--k; /* Decrements k then stores the new
value of k in i. */
● j=++l; /* Increments l then stores the new value
of l in j. */
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