a. Implement in C++ the external Merge sort algorithm given in Section 21.2 by using the functions seekg and seekp. Assume that the fi le to be sorted is a fi le of type int and that each block contains one integer. Further assume that the fi le contains 2 n integers for some integer n .
b. Now assume that each block contains many integers. Write C++ functions that simulate read Block and write Block. Implement externalMergesort by using these functions.
c. Extend your implementation of externalMergesort by removing the restriction that the fi le contains 2n blocks.