2D array manipulation using a pointer in C

2019-12-16 17:24发布

问题:

Let us say I have a function which manipulates a 2D array which receives a pointer to the 2D array from the main function as its parameter.

Now, I want to modify(assume add 10 to each element) each element of the 2D array.

I am interested in knowing about traversing through the 2D array with a single pointer given to me and return the pointer of the newly modified array.

Rough Structure

Assume pointer a contains the initial address of the 2D array.

int add_10(int *a)
{
    int i, j,
        b[M][N] = {0};

    for(i = 0; i < M; i++)
        for(j = 0; j < N; j++)
            b[i][j] = 10 + a[i][j];
}

回答1:

int* add_10(const int *dest,
            const int *src,
            const int M,
            const int N)
{
    int *idest = dest;

    memmove(dest, src, M * N * sizeof(int));

    for(int i = 0; i < (M * N); ++i)
        *idest++ += 10;

    return dest;
}