Programming :: C++ Search And Handle Information

I would like to make program that reads a *.TXT file and searches for last line and constatly refreshing the search. So last line would look something like this:Mike Had A 100.0 Pound Shark.So there are multplie category of "fish"(Shark, Dolphin, etc.) and each of them have allowed weight (ie. minimum 70.0 Pound Shark, 50.0 Pound Dolphin). If in the found sentence Shark or Dolphin doesn't meet requierments than program named False.exe should be started. I dont know how to make it my self so any help is much appreciated. My knowledge on programming is very low but I'm opend for learning.