C ++添加矩阵，程序已停止工作

Question

这是我的代码，程序崩溃但没有错误。 当我在声明的矩阵上测试时，matrixPrinter工作得很好

#include <iostream>
#include <vector>

std::vector< std::vector<int> > matrix1 = {
        {1,2,3},
        {1,2,3},
        {1,2,3}
    };

std::vector< std::vector<int> > matrix2 = {
        {1,2,3},
        {1,2,3},
        {1,2,3}
    };

std::vector< std::vector<int> > matrixAdder(std::vector< std::vector<int> > matrixA , std::vector< std::vector<int> > matrixB )
{
    std::vector< std::vector<int> > result;

    for(unsigned i = 0; i < matrixA.size(); i++)
    {
        for(unsigned j = 0; j < matrixB.size(); j++)
        {
            result[i][j] = matrixA[i][j] + matrixB[i][j];
        }
    }

    return result;
}

void matrixPrinter(std::vector< std::vector<int> > matrix)
{
    for(unsigned i = 0; i < matrix.size() ; i++)
    {
        std::cout << '|';
        for(unsigned j = 0; j < matrix[i].size() ; j++)
        {
            std::cout << ' ' << matrix[i][j] << ' ';
        }
        std::cout << '|';
        std::cout << std::endl;
    }
}

int main()
{
    matrixPrinter(matrixAdder(matrix1, matrix2));
}