C++ — Operators

Arithmetic operators

#include <iostream>
using namespace std;

int main() {
    int a = 10, b = 3;

    cout << "Add: " << a + b << endl;   // 13
    cout << "Sub: " << a - b << endl;   // 7
    cout << "Mul: " << a * b << endl;   // 30
    cout << "Div: " << a / b << endl;   // 3 (integer)
    cout << "Mod: " << a % b << endl;   // 1

    // Floating-point division
    cout << "10.0 / 3 = " << 10.0 / 3 << endl; // 3.33333

    return 0;
}

Increment and decrement

#include <iostream>
using namespace std;

int main() {
    int a = 5, b = 5;

    cout << "a++ = " << a++ << ", a = " << a << endl; // 5, 6
    cout << "++b = " << ++b << endl; // 6

    return 0;
}

Relational operators

#include <iostream>
using namespace std;

int main() {
    int a = 5, b = 10;

    cout << "Equal:     " << (a == b) << endl; // 0
    cout << "Not equal: " << (a != b) << endl; // 1
    cout << "Greater:   " << (a > b) << endl;  // 0
    cout << "Less:      " << (a < b) << endl;  // 1

    return 0;
}

Logical operators

#include <iostream>
using namespace std;

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

    cout << "AND: " << (a && b) << endl; // 0
    cout << "OR:  " << (a || b) << endl; // 1
    cout << "NOT: " << (!a) << endl;     // 0

    // Short-circuit evaluation
    int x = 0;
    if (x != 0 && 10 / x > 2) {
        cout << "Never reached" << endl;
    }

    return 0;
}

Bitwise operators

#include <iostream>
using namespace std;

int main() {
    unsigned int a = 0b1010; // 10
    unsigned int b = 0b1100; // 12

    cout << "AND: " << (a & b) << endl;   // 8
    cout << "OR:  " << (a | b) << endl;   // 14
    cout << "XOR: " << (a ^ b) << endl;   // 6
    cout << "NOT: " << ~a << endl;         // Large number
    cout << "Left:  " << (a << 1) << endl; // 20
    cout << "Right: " << (a >> 1) << endl; // 5

    return 0;
}

Assignment operators

#include <iostream>
using namespace std;

int main() {
    int x = 10;
    x += 5;   // 15
    x -= 3;   // 12
    x *= 2;   // 24
    x /= 4;   // 6
    x %= 4;   // 2
    x <<= 1;  // 4
    x >>= 1;  // 2

    cout << "Final: " << x << endl;
    return 0;
}

Ternary and conditional

#include <iostream>
using namespace std;

int main() {
    int age = 20;
    string status = (age >= 18) ? "Adult" : "Minor";
    cout << status << endl;

    // if expression (C++17)
    int x = 42;
    string label = [] {
        return "value";
    }();

    return 0;
}

sizeof and alignof

#include <iostream>
using namespace std;

int main() {
    cout << "char:     " << sizeof(char) << endl;
    cout << "int:      " << sizeof(int) << endl;
    cout << "double:   " << sizeof(double) << endl;

    struct Align {
        char a;
        int b;
        char c;
    };

    cout << "Struct size: " << sizeof(Align) << endl;
    cout << "Alignment:   " << alignof(Align) << endl;

    return 0;
}

Operator overloading

#include <iostream>
using namespace std;

class Vec2 {
public:
    float x, y;

    Vec2(float x, float y) : x(x), y(y) {}

    Vec2 operator+(const Vec2 &other) const {
        return Vec2(x + other.x, y + other.y);
    }

    bool operator==(const Vec2 &other) const {
        return x == other.x && y == other.y;
    }

    friend ostream &operator<<(ostream &os, const Vec2 &v) {
        return os << "(" << v.x << ", " << v.y << ")";
    }
};

int main() {
    Vec2 a(1, 2), b(3, 4);
    Vec2 c = a + b;
    cout << a << " + " << b << " = " << c << endl;
    cout << "Equal: " << (a == b) << endl;

    return 0;
}

Best practices

• Use parentheses when precedence is unclear
• Prefer == and != over implicit boolean conversions
• Use static_cast instead of C-style casts
• Override operators only when semantically meaningful
• Use constexpr for compile-time computations

Mini Practice

Write C++ code that:

1. Demonstrates all arithmetic operators
2. Shows short-circuit evaluation with &&
3. Overloads + and << for a simple class
4. Uses sizeof to check type sizes

Up Next

In the next lesson, you'll learn about Strings — working with std::string in C++.