Hi,
Sorry for being late! My excel sheet actually has data for the different contigs, their length, lengths of the 'Gap' that seperate each contig. Length of the chromosome and so on. My main program can create a random number and back calculate which chromosome and which contig on the chromosome that number will be long to, if we assume that entire human genome is a single gaint chromosome!

If you have anyother doubts please feel free to ask!
Sameet