2.1.2 Thinking ahead

• The purpose of thinking ahead is to make problems easy and intuitive for users to use.
• Inputs is data that is required to solve a problem, usually entered through a program by the user.
• Outputs is data, that are given by the program once the inputs have been processed.
• Three considerations programmers need to do when writing a program Inputs and Outputs is the order of data, the type of data inputted and methods of input and output.
• Preconditions are requirements programmers must make before a program must be executed.
• Caching is where data such as instructions or values are stored in cache memory after they have been used, as they may be used again
• Advantages of reusable programs are that they are more reliable as they have already been tested. It also saves: time, money and resources
• Two examples of reusable program components are classes and subroutines.