Now i am try to implement an External Sort.
I assume the computer only have 30 spaces to hold for the numbers. And now i am going to sort a 10000 numbers in a text file.
We take an array in 30 space, A[30] to represent the memory.
I can sort the file by creating 4 text file.
tape1.txt
tape2.txt
tape3.txt
tape4.txt
and sort the numbers.

but later i found out that we can use only 3 files to sort it and even more quickly....
Can anyone do it??