Question

I used the codes below to create dynamic memory.

unsigned int *mem  ;
mem = (unsigned int*) malloc(mallocSize);

However, I prefer to create an array of pointers.
Each pointers will link to one of the memory block.

Answer 1

but I prefer to create an array of pointers each pointer links to one of the memory block above

unsigned int **mem = (unsigned int **)malloc(sizeof(unsigned int *) * number_of_pointers);
// memset(mem, NULL, sizeof(unsigned int *) * number_of_pointers); // recommend it but not needed here, we always set NULL for safety.
for (int index = 0; index < number_of_pointers; index++)
    mem[index] = (unsigned int *)malloc(sizeof(unsigned int) * number_of_ints);

to access individual elements mem[row_index][column_index]

to de-allocate, to reduce or remove memory leaks.

for (int index = 0; index < number_of_pointers; index++)
    free(mem[index]);
free(mem);

rule of thumb, for me anyway, free should be call as often as malloc