27th October 1992. Previous pH reading. For the time being, this is simply a special variable that can store 128 key presses. Numbers can be conveniently stored as variables. Their contents may be changed throughout the program.
Variables can be of different types, depending on what sort of number they store.
The type of variable must be declared at the beginning of the program. Programmers must be sure of the range and type of numbers likely to be placed into variables before declaring them.