This a c code which will create a .vcf file with a list of contacts in it. This .vcf file can then be used to put random contacts in your mobile. It will become really difficult of the user to delete all the unwanted contacts from his phone. If the size of the .vcf file is too large the phone will hang.
Another use of this code is to hang the server. Just make the for loop iterate infinitely. Eventually the server will hang and no one will be able to perform ssh unless and until you close your program.