Final answer:
The function prototype for the GetLeast function in C++ is 'void GetLeast(ifstream& infile, int& lowest);'. It is a void function with reference parameters to allow modification of the arguments passed to it and simulate returning a value through the int parameter.
Step-by-step explanation:
The student is asking how to write the heading for a void function in C++ called GetLeast that takes an ifstream parameter named infile and an int parameter named lowest.
The infile parameter is used as an input that is modified within the function, whereas lowest is used to return a value by non-return function mechanism. The function prototype for GetLeast would be:
void GetLeast(ifstream& infile, int& lowest);
This prototype indicates that infile is passed by reference, and it will be used to read data from a file. The lowest parameter is also passed by reference, and it will be used to store the smallest value found during the function's execution, thus 'returning' a value even though the function itself does not return a value.
It should be noted, for documentation purposes, how data is expected to flow through these parameters:
- infile: The function expects this stream to be connected to an open file prior to the call and it will be used to read data within the function. The content of the file may affect the stream state (like its internal pointer will advance).
- lowest: This integer is intended to be modified by the function to reflect the least value read from the file attached to infile.