Section 7

Any data that a program uses which is stored in memory locations, has its own identifier, and has values in locations which may change when running

• Refers to location in memory where the data item is stored

• Defines type of data that will be stored at the memory location and therefore the operations that can be performed on it

integer - whole number real/float - number with fractional part char - single character (letter, digit, punctuation mark, symbol) string - zero or more characters, can be null boolean - value of true or false

Using an = sign

Changing the type of variable value from one type to another

Joining two strings together with +

Fixed Length

Group of fata items of the same data type

• Numerical reference called a subscript or index

Self- contained section of code that performs a specific task

• Procedures • Functions

Pass it one or more parameters

Variable named in procedure heading that will receive and use whatever value you pass it

Always return a value

Global Variables

• Decompose large problem into small tasks • Tested • Used several times • Stored in library • Work at same time • Maintenance easier

• Data structure • Treated as a set of data

• File • Held permanently on disk • Read next time needed

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