This metaphor almost certainly refers to the practice of establishing the first conditional check in a while
loop. If you don't do this, the loop won't work. It is a well-established pattern, and it hasn't changed since the while
loop was invented. The requirement for setting the initial condition in a while
loop is not a defect.
int i = 0; // prime the pump
while (i < 10)
{
Console.Write("While statement ");
Console.WriteLine(i);
i++; // set condition again
}
int i = 0; // prime the pump
while (i < 10)
{
Console.Write("While statement ");
Console.WriteLine(i);
i++; // set condition again
}
The primer can be a read statement, or whatever properly sets the initial condition. Setting the initial condition using a read statement is called a "Priming Read."
string line;
using (StreamReader file = new StreamReader("c:\\test.txt"))
{
line = file.ReadLine(); // Priming read.
while(line != null)
{
Console.WriteLine (line);
line = file.ReadLine(); // Subsequent reads.
}
}
string line;
using (StreamReader file = new StreamReader("c:\\test.txt"))
{
line = file.ReadLine(); // Priming read.
while(line != null)
{
Console.WriteLine (line);
line = file.ReadLine(); // Subsequent reads.
}
}
In C#, the two Readline()
calls can be combined into a single statement within the conditional:
while ((line = r.ReadLine()) != null)
{
Console.WriteLine (line);
}
while ((line = r.ReadLine()) != null)
{
Console.WriteLine (line);
}