Exercise 7-4: A private scanf

Write a private version of scanf analogous to minprintf from the previous section.

Handle the conversions d, o, x (into an int or unsigned), f (into a float), s and c, each with an optional field width, plus %%; white space in the format matches any amount of white space in the input, including none, and any other character must match itself. Return the number of values assigned, or EOF if the input ends before the first one, as scanf does.

Use it in a program that takes a format with one conversion as its argument and calls your scanf with it until that returns something other than 1, printing each value on a line of its own: integers in decimal, a float with %g, a string as it is, and a character inside brackets, like [a].