in C coding language:

Write a program "increment" that produces a file of sequential numbers, one per line, by reading the last number in the file, adding one to it, then appending the incremented number to the file. Have your program take as its first command line argument the number of times it will repeat this operation, and as its second command line argument the file to read/increment.

For example, increment 10 foo.txt shall open and read the file foo.txt, search for the last line (verifying that it has an integer N on it), then add 10 more lines with N+1, N+2, etc.

Write another program "consecutive" that reads a file of numbers, one per line, then outputs and two adjacent lines for which the number in the second line is not exactly one greater than the number in the first line. It shall read from standard in and write to standard out.