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Probably an extremely simple answer to this extremely simple question:
I'm reading "C Primer Plus" by Pratta and he keeps using the example
while (scanf("%d", &num) == 1)...
Is the == 1 really necessary? It seems like one could just write:
while (scanf("%d", &num))
It seems like the equality test is unnecessary since scanf returns the number of objects read and 1 would make the while loop true. Is the reason to make sure that the number of elements read is exactly 1 or is this totally superfluous?
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scanf() function returns number of items it successfully reads. Since in your case it is reading one number n , scanf() returns 1. When you give a input file for the code to run, it returns 0 on reaching end of the file (EOF).
That is because there is a left over newline character in the input buffer.
Try to compile this program and run it, and you will see you can use scanf() inside an if, else or else if clause.
You can use the scanf() function to read a string. The scanf() function reads the sequence of characters until it encounters whitespace (space, newline, tab, etc.).
In C, 0 is evaluated to false and everything else to true. Thus, if scanf returned EOF, which is a negative value, the loop would evaluate to true, which is not what you'd want.
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