Data types in COBOL

Alphanumeric - may contain letters, spaces, and special characters

Alphabetic - may contain only letters of the alphabet and spaces

Numeric - may contain numbers. The variable may be declared as signed or unsigned

In COBOL you can specify how the numeric data is stored in memory by the USAGE clause

USAGE IS DISPLAY - means that each numeral or digit requires one byte of storage

USAGE IS PACKED - DECIMAL means two digits can be stored in one byte of storage.

USAGE IS BINARY - means numbers are stored in binary form. Binary form is usually the most efficient way to store numeric data.