C++ Logical Operators

Introduction

Logical operators in C++ are used to perform logical operations on boolean values. They are essential for controlling the flow of your program using conditions, combining multiple conditions, and making decisions based on these conditions. Logical operators return a boolean value (true or false) based on the logic they perform.

List of Logical Operators

1. Logical AND (&&): Returns true if both operands are true.
2. Logical OR (||): Returns true if at least one of the operands is true.
3. Logical NOT (!): Returns true if the operand is false, and false if the operand is true.

Logical Operators with Examples

Logical AND (&&)

The logical AND operator returns true if both operands are true. If either operand is false, it returns false.

Example

#include <iostream>
using namespace std;

int main() {
    bool a = true;
    bool b = false;

    bool result = a && b; // Checks if both a and b are true

    cout << "a && b: " << result << endl; // Output the result
    return 0;
}

Output

a && b: 0

Logical OR (||)

The logical OR operator returns true if at least one of the operands is true. If both operands are false, it returns false.

Example

#include <iostream>
using namespace std;

int main() {
    bool a = true;
    bool b = false;

    bool result = a || b; // Checks if at least one of a or b is true

    cout << "a || b: " << result << endl; // Output the result
    return 0;
}

Output

a || b: 1

Logical NOT (!)

The logical NOT operator returns true if the operand is false, and false if the operand is true.

Example

#include <iostream>
using namespace std;

int main() {
    bool a = true;

    bool result = !a; // Checks if a is false

    cout << "!a: " << result << endl; // Output the result
    return 0;
}

Output

!a: 0

Combining Logical Operators

Logical operators can be combined to create complex logical expressions.

Example

#include <iostream>
using namespace std;

int main() {
    bool a = true;
    bool b = false;
    bool c = true;

    // Combining logical operators
    bool result = (a && b) || (b && c) || (a && c);

    cout << "(a && b) || (b && c) || (a && c): " << result << endl; // Output the result
    return 0;
}

Output

(a && b) || (b && c) || (a && c): 1

Explanation

1. Logical AND (&&)

   • Returns true if both operands are true.
   • Example: a && b returns false because b is false.

2. Logical OR (||)

   • Returns true if at least one of the operands is true.
   • Example: a || b returns true because a is true.

3. Logical NOT (!)

   • Returns true if the operand is false, and false if the operand is true.
   • Example: !a returns false because a is true.

4. Combining Logical Operators

   • (a && b) || (b && c) || (a && c) combines multiple logical operators to form a complex expression.
   • This expression evaluates to true because (a && c) is true.

Conclusion

Logical operators are essential tools in C++ for performing logical operations on boolean values. This chapter covered the logical AND (&&), logical OR (||), and logical NOT (!) operators with simple examples and their outputs. Understanding these operators will help you create complex conditional logic and control the flow of your programs more effectively. In the next chapter, we will explore bitwise operators in C++.