Overview

safe-c introduces three distinct data types. A data type is a particular format for storing information of some particular kind. The three safe-c data types are:

• boolean_type: This only has two possible values, denoted by the symbolic constants TRUE and FALSE. It is used particularly when the behaviour of the program is to depend on whether some condition is satisfied - whether it is true or not.
• integer_type: For dealing with positive or negative whole, or integer, numbers. This type cannot be used to deal with non-integer numbers, such as fractions.
• floating_point_type: This is a special kind of format which can handle non-integer, rational, numbers (i.e. there is a decimal point) but the position of the decimal point is not fixed. That is, these numbers have a fixed degree of precision - a fixed number of significant digits - but the decimal point can be located anywhere. The decimal point is said to float. Floating points formats are essentially similar to conventional scientific notation such as .
• string_type: For storing strings of characters, of variable length.

safe-c provides functions - or "subprograms" if you like - to carry out various standard manipulations on objects of these standard types. Specifically, there are functions to display strings in the MS-DOS window, and to read strings in from the keyboard; and to convert between string representations and the internal binary representations of boolean_type, integer_type and floating_point_type. In this way, objects of these types can be read in from the keyboard (as string_type), converted to one of the internal binary representations, operated upon in any appropriate way (i.e. performing boolean or arithmetic operations) and the results can be displayed again.