547: Mainline

So far, you have seen two ways to write the main–readData combination:

• You create an array in main. The address of the memory representing the array is assigned to a variable in main. Then, you hand over the address to readData, where it is assigned to a parameter. On return, the address is handed back, and again is assigned to the variable in main from whence it came.
• You create an array in main. The address of the memory representing the array is assigned to a variable in main. Then, you hand over the address to readData, where it is assigned to a parameter. Nothing is returned, but the changes to the array stick, because only the address is copied on entering readData, and the array elements are not copied.

There is another alternative:

• You only declare an array variable in main. Thus, there is no array to hand to readData. Instead, you create the array in readData, and hand it back as the value of readData.