C++ or_eq Keyword

The or_eq keyword in C++ is an alternative representation of the bitwise OR assignment operator (|=). It is part of the alternative tokens introduced in the C++ Standard to improve code readability and accessibility for programmers using different keyboard layouts.

The or_eq operator performs a bitwise OR operation between two operands and assigns the result to the left-hand operand.

Syntax

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variable or_eq expression;
or_eq
The keyword representing the bitwise OR assignment operator.
variable
The left-hand operand, which stores the result of the operation.
expression
The right-hand operand to perform the bitwise OR operation with.

Examples

Example 1: Basic Use of or_eq

This example demonstrates the equivalence of or_eq and |=.

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#include <iostream>
using namespace std;

int main() {
    int a = 5;  // Binary: 0101
    int b = 3;  // Binary: 0011

    a or_eq b;  // Same as a |= b

    cout << "Result of a or_eq b: " << a << endl;

    return 0;
}

Output:

Result of a or_eq b: 7

Explanation:

  1. The binary representation of 5 is 0101, and 3 is 0011.
  2. The or_eq operation performs a bitwise OR, resulting in 0111 (decimal 7).
  3. The result is stored in a, and the output displays the updated value of a.

Example 2: Using or_eq in a Loop

The or_eq keyword can be used in loops to combine multiple values into a single result.

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#include <iostream>
using namespace std;

int main() {
    int result = 0; // Binary: 0000
    int values[] = {1, 2, 4}; // Binary: 0001, 0010, 0100

    for (int value : values) {
        result or_eq value; // Same as result |= value
    }

    cout << "Final result: " << result << endl;

    return 0;
}

Output:

Final result: 7

Explanation:

  1. The binary representation of 1, 2, and 4 is combined using or_eq.
  2. The cumulative result is 0111 (decimal 7).
  3. The loop iteratively applies the or_eq operation to combine the values.

Example 3: Using or_eq for Bitmask Operations

The or_eq keyword is commonly used in bitmask operations to set specific bits in a variable.

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#include <iostream>
using namespace std;

int main() {
    int flags = 0;      // Binary: 0000
    int mask1 = 1;      // Binary: 0001
    int mask2 = 4;      // Binary: 0100

    flags or_eq mask1;  // Set the first bit
    flags or_eq mask2;  // Set the third bit

    cout << "Flags after bitmask operations: " << flags << endl;

    return 0;
}

Output:

Flags after bitmask operations: 5

Explanation:

  1. The binary representation of flags starts as 0000.
  2. The first or_eq operation sets the first bit, resulting in 0001.
  3. The second or_eq operation sets the third bit, resulting in 0101 (decimal 5).

Key Points to Remember about or_eq Keyword

  • or_eq is an alternative representation of the bitwise OR assignment operator (|=).
  • It performs a bitwise OR operation between two operands and assigns the result to the left-hand operand.
  • It is part of the alternative tokens introduced to enhance code readability and accessibility.
  • It is commonly used in bitmask operations to set specific bits in a variable.
  • Using or_eq is optional and depends on coding style or preferences.