data structures using pointer to three-dimensional array can be declared asint arr[ ][ ][ ]={ , , , , , , , }int (*parr)[ ][ ]parr arrwe can access an element of three-dimensional array by writingarr[ ][ ][ *(*(*(arr+ )+ )+kprogramming example write program which illustrates the use of pointer to three-dimensional array #include #include int main(int , ,kint arr[ ][ ][ ]int (*parr)[ ][ ]arrclrscr()printf("\ enter the elements of array")for( ++for( ++for( ++scanf("% "&arr[ ][ ][ ])printf("\ the elements of the array are")for( ++for( ++for( ++printf("% "*(*(*(parr+ )+ )+ ))getch()return output enter the elements of array the elements of the array are note in the printf statementyou could also have used instead of *(*(*(parr+ )+ )+ ) sparse matrices sparse matrix is matrix that has large number of elements with zero value in order to efficiently utilize the memoryspecialized algorithms and data structures that take advantage of the sparse structure should be used if we apply the operations using standard matrix structures and algorithms to sparse matricesthen the execution will slow down and the matrix will consume large amount of memory sparse data can be easily compressedwhich in turn can significantly reduce memory usage