Coercion: Case Studies

FORTRAN 77: Only Widening

• INTEGER -> REAL -> COMPLEX or DOUBLE PRECISION

C: Automatic conversion in expressions, parameter

• short -> int
• float -> double (not ANSI C/C++)

C++:

• Expressions: widening only
• Assignment: Widening or narrowing

Ada/Modula-2: Very few mixed expressions o.k

• When using Subranges

PL/I:

• Can mix integers and characters (value interpreted)

Disadvantages:

• Reduced error detection
• Expensive type check/run time conversion