When you enter a data value on the screen, you type an ASCII string representation of the value. This ASCII strings must be converted to the binary representation is order to be used by a C/Base program.
C/Base uses two processed in converting ASCII values. First, the appropriate format is "matched" against the input string. If the string complies with the format, the value is converted according to the format. If the string does not match the format, a set of standard input rules (one per data type) is applied to the string to perform the necessary conversion.
The rules for formats have already been covered in the Output Format section. There are some special cases for input and these are noted below. The remainder of this section discusses the standard input rules and any special cases of the formats. Keep in mind that the standard rules discussed below are applied only after the input string fails to match the format.