C ++：函数模板

Question

I have 2 2D arrays that represent a maze

const char maze1[10][11] and const char maze2[20][21]

I'm trying to create 1 function to handle both mazes like so:

void solveMaze(maze[][])
{
}

and just pass the maze like solveMaze(maze1);

How would I do this with function templates?

I recently asked this question already but explicitly asked not to use function templates because I wasn't sure on how to use it, but I would like to see how it would work. (hope this isn't "abusing" the system)

Answer 1

You do not need and should not use templates to solve this problem. All you are doing is solving mazes of different sizes.

Templates are for the generation of a number of classes/functions that use various types.

Instead construct a class to store a maze. This class should store the dimentsions of the maze and give access to the components of that maze.

Answer 2

First of all, it would be much simpler if you were using better arrays. The issue with C-arrays is that they have a tendency to decay to pointers easily, and once they do, the size is lost (and that, my dear, is pretty stupid as far as I am concerned...)

The choice then depends on whether you have fixed-size arrays or want dynamically-sized arrays:

• for fixed-size: std::array (or if unavailable boost::array )
• for dynamically-size: std::vector

Since a template will make more sense in the std::array case, I'll suppose that is what you elected.

char const maze1[10][11]

is equivalent to

std::array<std::array<char, 11>, 10> const maze1

It's slightly more verbose, but std::array proposes regular member methods like .size() , .begin() , .end() , etc... and it can be passed in functions easily.

Now, on to your template functions. The signature will simply be:

template <size_t M, size_t N>
void solveMaze(std::array<std::array<char, N>, M> const& maze);

However, despite your question, you more likely want not to use templates here (they are of little benefits). So I would advise using vector and a regular functions:

void solveMaze(std::vector< std::vector<char> > const& maze);

Answer 3

template<int w, int h>
void solveMaze(const char (&maze)[w][h])
{
    //can use w,h now
} 

Answer 4

There is no real support for multidimensional Arrays. You should consider using a class with proper support for the dimensions. The following does the trick

template<int N, int M>
void solveMaze(const char (&maze)[N][M]) {
    size_t n = N;
    size_t m = M;
    int x = 0;
}

int main(int argc, char *argv[])
{
    const char maze[3][2] = { { 0, 1} , {2, 3}, {4, 5} };
    solveMaze(maze);
    return 0;
}