HP C A.06.05 Reference Manual

Expressions and Operators
Conditional Expression Operator (?:)
Chapter 5104
Conditional Expression Operator (?:)
Syntax
exp1 ? exp2 : exp3
Arguments
exp1 Any expression.
exp2 Any expression.
exp3 Any expression.
Description
The conditional expression construction provides a shorthand way of coding an if…else
condition. The difference between the expression notation and an if…else condition is that
the ?:notation is an expression and therefore returns a value, while an if…else condition is
a statement and does not return a value. The syntax described above is equivalent to
if (exp1)
exp2;
else
exp3;
When a conditional expression is executed, exp1 is evaluated first. If it is true (that is,
nonzero) exp2 is evaluated and its result is the value of the conditional expression. If exp1 is
false, exp3 is evaluated and its result is the value of the conditional expression.
There is no requirement that you put parentheses around the exp1 portion of the conditional
expression, but doing so will improve your code's readability.
Both exp2 and exp3 must be assignment-compatible. If exp2 and exp3 are pointers to
different types, then the compiler issues a warning. The value of a conditional expression is
either exp2 or exp3 , whichever is selected. The other expression is not evaluated. The type of
the result is the type that would be produced if exp2 and exp3 were mixed in an expression.
For instance, if exp2 is a char and exp3 is a double, the result type will be double regardless of
whether exp2 or exp3 is selected.