6 Questions
What is the difference between the prefix and postfix increment operators?
In prefix mode (++val), the operator increments the value of the variable first, then returns the incremented value. In postfix mode (val++), the operator returns the original value, then increments the variable.
Which of the following statements is equivalent to val = val + 1?
Both (a) and (b)
In the expression cout << ++val << val++;, what is the output if the initial value of val is 5?
6 5
What is the output of the following code snippet?
int x = 10;
cout << x++ << ' ' << ++x;
10 12
Which operator is used to decrement the value of a variable by 1?
--
What is the output of the following code snippet?
int a = 5, b = 10;
a = a++ + ++b;
cout << a << ' ' << b;
16 12
Study Notes
Increment and Decrement Operators
- The increment operator is
++, which adds one to a variable. -
val++;is equivalent toval = val + 1; - The increment operator can be used in two ways:
- Prefix:
++val;(increments the variable, then returns the value) - Postfix:
val++;(returns the value of the variable, then increments)
- Prefix:
Decrement Operator
- The decrement operator is
--, which subtracts one from a variable. -
val--;is equivalent toval = val - 1; - The decrement operator can also be used in two ways:
- Prefix:
--val;(decrements the variable, then returns the value) - Postfix:
val--;(returns the value of the variable, then decrements)
- Prefix:
Using Increment and Decrement Operators in Programs
- Increment and decrement operators can be used in complex statements and expressions.
- It is important to understand the difference between prefix and postfix operators to avoid unexpected results.
Test your knowledge on the increment and decrement operators in C++ with this quiz based on Chapter 5 of the 'Starting Out with C++ 9th Edition' book. Understand how ++ and -- operators work as both prefix and postfix. Copyright © 2019, 2016, 2012 Pearson Education, Inc.
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