add to source, compile and run. very brief example usage (basically just the calling syntax) included in the commentstwo functions; the first dynamically allocates a 2D array with a user- or program-specified number of rows/columns; the second deallocates the same array. demonstrates the mutlti-dimensional usage of malloc and free.
/* allocate2D
/* function to dynamically allocate 2-dimensional array using malloc.
/*
/* accepts an int** as the "array" to be allocated, and the number of rows and
/* columns.
*/
void allocate2D(int** array, int nrows, int ncols) {
/* allocate array of pointers */
array = ( int** )malloc( nrows*sizeof( int* ) );
/* allocate each row */
int i;
for(i = 0; i < nrows; i++) {
array[i] = ( int* )malloc( ncols*sizeof( int ) );
}
}
/* deallocate2D[Click Here](null)
/* corresponding function to dynamically deallocate 2-dimensional array using
/* malloc.
/*
/* accepts an int** as the "array" to be allocated, and the number of rows.
/* as with all dynamic memory allocation, failure to free malloc'ed memory
/* will result in memory leaks
*/
void deallocate2D(int** array, int nrows) {
/* deallocate each row */
int i;
for(i = 0; i < nrows; i++) {
free(array[i]);
}
/* deallocate array of pointers */
free(array);
}
/* EXAMPLE USAGE:
int** array1;
allocate2D(array1,1000,1000); //allocates a 1000x1000 array of ints
deallocate2D(array1,1000); //deallocates the same array
*/