Assignment operators in C++ tutorials

Assignment operators in C++ are used to assign values to variables.

The most common assignment operator is =, but C++ also provides compound assignment operators, which combine arithmetic or bitwise operations with assignment in a single step.

These operators help make code more concise and efficient.

List of Assignment Operators in C++

1. Basic Assignment Operator (=)

The = operator assigns the value of the right operand to the left operand.

#include <iostream>
using namespace std;

int main() {
    int x;
    x = 10; // Assign 10 to x

    cout << "Value of x: " << x << endl;
    return 0;
}

Explanation:

• x = 10 assigns the value 10 to x.

Output:

Value of x: 10

2. Add and Assign (+=)

The += operator adds the right operand to the left operand and assigns the result to the left operand.

#include <iostream>
using namespace std;

int main() {
    int x = 5;
    x += 10; // x = x + 10

    cout << "After += 10, x: " << x << endl;
    return 0;
}

Explanation:

• x += 10 adds 10 to x, so x becomes 15.

Output:

After += 10, x: 15

3. Subtract and Assign (-=)

The -= operator subtracts the right operand from the left operand and assigns the result to the left operand.

#include <iostream>
using namespace std;

int main() {
    int x = 20;
    x -= 5; // x = x - 5

    cout << "After -= 5, x: " << x << endl;
    return 0;
}

Explanation:

• x -= 5 subtracts 5 from x, so x becomes 15.

Output:

After -= 5, x: 15

4. Multiply and Assign (*=)

The *= operator multiplies the left operand by the right operand and assigns the result to the left operand.

#include <iostream>
using namespace std;

int main() {
    int x = 4;
    x *= 5; // x = x * 5

    cout << "After *= 5, x: " << x << endl;
    return 0;
}

Explanation:

• x *= 5 multiplies x by 5, so x becomes 20.

Output:

After *= 5, x: 20

5. Divide and Assign (/=)

The /= operator divides the left operand by the right operand and assigns the result to the left operand.

#include <iostream>
using namespace std;

int main() {
    int x = 20;
    x /= 4; // x = x / 4

    cout << "After /= 4, x: " << x << endl;
    return 0;
}

Explanation:

• x /= 4 divides x by 4, so x becomes 5.

Output:

After /= 4, x: 5

6. Modulus and Assign (%=)

The %= operator takes the modulus of the left operand by the right operand and assigns the result to the left operand.

#include <iostream>
using namespace std;

int main() {
    int x = 10;
    x %= 3; // x = x % 3

    cout << "After %= 3, x: " << x << endl;
    return 0;
}

Explanation:

• x %= 3 calculates 10 % 3, which results in 1, so x becomes 1.

Output:

After %= 3, x: 1

7. Bitwise AND and Assign (&=)

The &= operator performs a bitwise AND on the left and right operands and assigns the result to the left operand.

#include <iostream>
using namespace std;

int main() {
    int x = 5;   // Binary: 0101
    x &= 3;      // Binary: 0011

    cout << "After &= 3, x: " << x << endl; // Output: 1
    return 0;
}

Explanation:

• x &= 3 performs 0101 & 0011, resulting in 0001, so x becomes 1.

Output:

After &= 3, x: 1

8. Bitwise OR and Assign (|=)

The |= operator performs a bitwise OR on the left and right operands and assigns the result to the left operand.

#include <iostream>
using namespace std;

int main() {
    int x = 5;   // Binary: 0101
    x |= 3;      // Binary: 0011

    cout << "After |= 3, x: " << x << endl; // Output: 7
    return 0;
}

Explanation:

• x |= 3 performs 0101 | 0011, resulting in 0111, so x becomes 7.

Output:

After |= 3, x: 7

9. Bitwise XOR and Assign (^=)

The ^= operator performs a bitwise XOR on the left and right operands and assigns the result to the left operand.

#include <iostream>
using namespace std;

int main() {
    int x = 5;   // Binary: 0101
    x ^= 3;      // Binary: 0011

    cout << "After ^= 3, x: " << x << endl; // Output: 6
    return 0;
}

Explanation:

• x ^= 3 performs 0101 ^ 0011, resulting in 0110, so x becomes 6.

Output:

After ^= 3, x: 6

10. Left Shift and Assign (<<=)

The <<= operator shifts the bits of the left operand to the left by the number of positions specified by the right operand, and assigns the result to the left operand.

#include <iostream>
using namespace std;

int main() {
    int x = 3;   // Binary: 0011
    x <<= 1;     // Shift left by 1 position

    cout << "After <<= 1, x: " << x << endl; // Output: 6
    return 0;
}

Explanation:

• x <<= 1 shifts 0011 one position to the left, resulting in 0110, so x becomes 6.

Output:

After <<= 1, x: 6

11. Right Shift and Assign (>>=)

The >>= operator shifts the bits of the left operand to the right by the number of positions specified by the right operand, and assigns the result to the left operand.

#include <iostream>
using namespace std;

int main() {
    int x = 8;   // Binary: 1000
    x >>= 1;     // Shift right by 1 position

    cout << "After >>= 1, x: " << x << endl; // Output: 4
    return 0;
}

Explanation:

• x >>= 1 shifts 1000 one position to the right, resulting in 0100, so x becomes 4.

Output:

After

 >>= 1, x: 4

12. Summary Table of Assignment Operators in C++

Complete Example: Using Assignment Operators

This example demonstrates various assignment operators by initializing a variable and applying different compound assignment operators to it.

#include <iostream>
using namespace std;

int main() {
    int x = 10;

    x += 5;
    cout << "After += 5, x: " << x << endl;

    x -= 2;
    cout << "After -= 2, x: " << x << endl;

    x *= 3;
    cout << "After *= 3, x: " << x << endl;

    x /= 4;
    cout << "After /= 4, x: " << x << endl;

    x %= 3;
    cout << "After %= 3, x: " << x << endl;

    x <<= 1;
    cout << "After <<= 1, x: " << x << endl;

    x >>= 1;
    cout << "After >>= 1, x: " << x << endl;

    x &= 2;
    cout << "After &= 2, x: " << x << endl;

    x |= 1;
    cout << "After |= 1, x: " << x << endl;

    x ^= 3;
    cout << "After ^= 3, x: " << x << endl;

    return 0;
}

Output:

After += 5, x: 15
After -= 2, x: 13
After *= 3, x: 39
After /= 4, x: 9
After %= 3, x: 0
After <<= 1, x: 0
After >>= 1, x: 0
After &= 2, x: 0
After |= 1, x: 1
After ^= 3, x: 2

Assignment operators in C++ simplify common operations by combining them with assignment in a single step.