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21. (12 pts) Write a void function definition that is described below: The name of the void function is Openlnput The function has one parameter - an input file stream The function is to: a) Prompt the user for the name of an input file and read it. b) Open the file c) If the file did not open successfully, print out a message stating as such, reset the input stream variable (code to do this is inFile.clear):) d) Repeat steps a,b,c until a file is successfully opened or the user enters ctrl-c