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Table of contents
1.
Introduction
2.
What is boolean in C++?
2.1.
Syntax
2.2.
 
2.3.
Example
2.4.
C++
2.4.1.
 
2.4.2.
Output
3.
How do C++ Booleans value come into play while programming?
3.1.
Code
3.2.
C++
3.2.1.
Output
3.3.
Explanation
4.
Why is the C++ Booleans Type Useful?
5.
Points to Remember:
5.1.
Example:
6.
Converting Non-Boolean Types to Boolean
7.
Converting Integers and Floating Point Numbers to Boolean
8.
Advantages of C++ Booleans
9.
Disadvantages of C++ Booleans
10.
Frequently Asked Questions
10.1.
What are the three states of boolean in C++?
10.2.
What is boolean used for in C++?
10.3.
What are C++ Booleans?
10.4.
What are the boolean operators in C++?
10.5.
Is Boolean 0 or 1 in C++?
11.
Conclusion 
Last Updated: Apr 4, 2024
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C++ Booleans

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Introduction

In C++, the boolean data type is declared using the word bool. By default, the value true is represented by 1 and false by 0 in boolean variables.

There are certain times when we need yes/no as an answer. For example, the answer to the question “Do dogs bark?” would be Yes. There are certain times in Coding too, when we need yes or no as an answer. Boolean variables are used exactly for this purpose.

C++ Booleans

This blog will discuss C++ Booleans in detail along with some examples.

What is boolean in C++?

C++ has various data types, including Int, double, float, char, and boolean. A C++ booleans data type is used to hold only two values; it can be either True or False.

In C++, 1 refers to True, and 0 refers to False. Let’s see the syntax for defining a C++ booleans variable.

c++ booleans

You can also do a free certification of Basics of C++.

Syntax

bool <Variable Name> = true;

 

Example

  • C++

C++

#include <bits/stdc++.h>
using namespace std;

int main()
{
   bool a = true;
   cout<<a<<endl;

   return 0;
}

 

Output

1

 

You might be wondering, We can use an integer data type if we want to hold 1 or 0, then what is the necessity of using a boolean data type? 

boolean example

A simple explanation for this query is that the integer data type can store all kinds of integer values but the boolean data type stores the value either 0 or 1 whose primary focus is to state whether the statement is true or false.

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How do C++ Booleans value come into play while programming?

C++ Booleans values are used to describe conditions and regulate how the programs respond to specific events (e.g. if a condition is true, then do something otherwise, do something else according to the program). 

In simple words, the bool datatype is most frequently used in conditional expressions. We can compare two values in a condition and return a boolean output.

Let's see how they are used in conditional statements:

Code

  • C++

C++

#include <bits/stdc++.h>
using namespace std;
int main()
{
   // declaring variables
   int var1 = 20;
   int var2 = 30;
   bool ans;
   // conditional statements
   ans = var1 == var2;


   if (ans)
   {
       cout << "The two numbers are equal";
   }
   else if (!ans)
   {
       cout << "The two numbers are not equal.";
   }
   return 0;
}

 

Output

The two numbers are not equal.

 

You can try and compile with the help of online c++ compiler.

Explanation

In the above program, we took two integers and compared them if they are equal or not. And then, we checked if the boolean variable is true, printing “The two numbers are equal”. If it is false, print “ The two numbers are not equal.” 

We can also directly print 0 or 1 just by not assigning the task in an if-else statement.

Why is the C++ Booleans Type Useful?

In C++, using a boolean variable means specifying that it can only take one of two possible values: true (1) or false (0). This aids in limiting the range of if statements to a true or false input. If we convert our variable to an integer, there could be problems if it is given a value other than a 1 or a 0.

Points to Remember:

  •  The default value of a boolean variable is false.
  •  The default numeric value of true is 1, and for false, it is 0.
  •  Mathematical expressions can also make use of bool-type variables or true and false values.

 

Example:

int ans = true + false;

The value of ans will be 1.

Additionally, it is possible to implicitly transform floating point or integer data to the bool type.

Converting Non-Boolean Types to Boolean

Using implicit or explicit type conversion, non-boolean types in C++ can be transformed into booleans. This means considering values other than zero as true and zero as false. Utilize constructs like bool(value) or value!= 0 for explicit conversion. Remember that precision could be lost through these conversions, so use caution while using them.

Converting Integers and Floating Point Numbers to Boolean

In C++, boolean values can be created from integers and floating-point numbers. Zero is regarded as false while any non-zero integer or non-zero floating-point number is true. Either explicit or implicit type casting can be used to accomplish this conversion. Use constructs like bool(value) or value!= 0.0 for floating-point values to convert anything explicitly. A word of caution should be used when converting floating-point integers because precision constraints do apply.

Advantages of C++ Booleans

Some advantages of C++ Booleans are:-

  • Readability and Simplicity: Booleans in C++ make code easier to understand and read. They express true or false values explicitly, which helps make the logic and conditions in the code more understandable
     
  • Efficient Memory Usage: Despite being considered a whole datatype conceptually, booleans typically only use one bit of RAM to store them. They become memory-efficient as a result, which is particularly useful for making the most of available space
     
  • Logical Operation: Booleans are the fundamental building blocks of logical operations. They are crucial in conditional statements, loops, and other control structures so that programs may make wise decisions
     
  • Behavior: Booleans behave consistently across different C++ implementations, which makes code more adaptable and dependable across a range of platforms and compilers
     

Disadvantages of C++ Booleans

Some disadvantages of C++ Booleans are:-

  • Potential for Misuse: Booleans have the potential to be misused because of their simplicity, especially by new programmers. For instance, it could be confusing and error-prone to use a boolean to describe a complex state
     
  • Limited Range of Values: Booleans only represent the true and false states, which limits their range of values. When more sophisticated or nuanced states need to be communicated, this simplicity may not be ideal
     
  • Potential for Type Mismatch: Using booleans in complex expressions or interacting with other code might occasionally result in a type mismatch. Errors and unexpected behavior may result from this
     
  • Less Expressive Than Enums: Enums or other custom types may be more appropriate than booleans in situations where many states need to be expressed since they allow a larger range of values
     

Check out this article - C++ String Concatenation

Frequently Asked Questions

What are the three states of boolean in C++?

A boolean in C++ can exist in one of three states: true, which denotes a condition that evaluates to logically true; false, which denotes a condition that evaluates to logically false; or uninitialized, which happens when a boolean variable has not yet been assigned a value. 

What is boolean used for in C++?

A boolean in C++ can exist in one of three states: true, which denotes a condition that evaluates to logically true; false, which denotes a condition that evaluates to logically false; or uninitialized, which happens when a boolean variable has not yet been assigned a value. 

What are C++ Booleans?

C++ Booleans are a data type representing true or false values.

What are the boolean operators in C++?

Boolean operators in C++ include logical AND (&&), logical OR (||), and logical NOT (!).

Is Boolean 0 or 1 in C++?

In C++, true is typically represented as 1 and false as 0.

Conclusion 

In this blog, we have discussed what are C++ Booleans, along with some examples. Understanding C++ Booleans and their usage is essential for any programmer embarking on their journey in C++ development. Booleans serve as the backbone of decision-making in programming logic, enabling developers to create robust and efficient algorithms.  If you want to learn more, check out our articles. 

Recommended Readings:


To learn more about Data Structures and Algorithms, you can enroll in our DSA in C++ Course.

Happy Learning!

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