Implement a C++ class called "Matrix" that represents a 2D matrix of integers. The class should have methods for addition, subtraction, and multiplication of matrices, along with a method to print the matrix in a readable format. Ensure proper error handling for incompatible matrix operations.

```cpp
#include <iostream>
#include <vector>

class Matrix {
public:
    Matrix(int rows, int cols) : data(rows, std::vector<int>(cols)) {}

    // Getters for number of rows and columns
    int getRows() const { return data.size(); }
    int getCols() const { return data[0].size(); }

    // Access matrix elements
    int& operator()(int row, int col) { return data[row][col]; }
    const int& operator()(int row, int col) const { return data[row][col]; }

    // Addition
    Matrix operator+(const Matrix& other) const {
        if (getRows() != other.getRows() || getCols() != other.getCols()) {
            throw std::invalid_argument("Matrices have incompatible dimensions for addition.");
        }

        Matrix result(getRows(), getCols());
        for (int i = 0; i < getRows(); ++i) {
            for (int j = 0; j < getCols(); ++j) {
                result(i, j) = (*this)(i, j) + other(i, j);
            }
        }
        return result;
    }

    // Subtraction
    Matrix operator-(const Matrix& other) const {
        if (getRows() != other.getRows() || getCols() != other.getCols()) {
            throw std::invalid_argument("Matrices have incompatible dimensions for subtraction.");
        }

        Matrix result(getRows(), getCols());
        for (int i = 0; i < getRows(); ++i) {
            for (int j = 0; j < getCols(); ++j) {
                result(i, j) = (*this)(i, j) - other(i, j);
            }
        }
        return result;
    }

    // Multiplication
    Matrix operator*(const Matrix& other) const {
        if (getCols() != other.getRows()) {
            throw std::invalid_argument("Matrices have incompatible dimensions for multiplication.");
        }

        Matrix result(getRows(), other.getCols());
        for (int i = 0; i < getRows(); ++i) {
            for (int j = 0; j < other.getCols(); ++j) {
                int sum = 0;
                for (int k = 0; k < getCols(); ++k) {
                    sum += (*this)(i, k) * other(k, j);
                }
                result(i, j) = sum;
            }
        }
        return result;
    }

    // Print matrix
    void print() const {
        for (int i = 0; i < getRows(); ++i) {
            for (int j = 0; j < getCols(); ++j) {
                std::cout << (*this)(i, j) << " ";
            }
            std::cout << std::endl;
        }
    }

private:
    std::vector<std::vector<int>> data;
};

int main() {
    Matrix A(2, 3);
    Matrix B(3, 2);

    A(0, 0) = 1; A(0, 1) = 2; A(0, 2) = 3;
    A(1, 0) = 4; A(1, 1) = 5; A(1, 2) = 6;

    B(0, 0) = 7; B(0, 1) = 8;
    B(1, 0) = 9; B(1, 1) = 10;
    B(2, 0) = 11; B(2, 1) = 12;

    Matrix C = A * B;
    C.print();

    return 0;
}
```