Conditional Structures and Loops - A Concise and Practical Introduction to Programming Algorithms in Java - page 34

2.2.2 Ternary operator for branching instructions:
Predicate ? A : B

In Java, there is also a special compact form of the if else conditional
used for variable assignments called a ternary operator. This ternary operator
Predicate ? A : B provided for branching assignments is illustrated in the
sample code below:

double x1=Math . PI ; // constants defined in the Math class
double x2=Math .E;
double min=(x1 > x2) ? x2 : x1 ; // min value
double diff= (x1 > x2) ? x1 − x2 : x2 − x1 ; // absolute value
System . out . println (min+ " difference with max=" +diff ) ;

Executing this code, we get:
2.718281828459045 difference with max=0.423310825130748

The compact instruction
double min=(x1>x2)? x2 : x1;

...is therefore equivalent to:

double min;
if (x1>x2) min=x2;
else min=x1;

Figure 2.1 depicts the schema for unary, binary and ternary operators.

Unary operator Binary operator Ternary operator

++

* ?:

a a b Predicate a

b

(Predicate? a : b)

a++ a*b

post-incrementation multiplication compact branching

Figure 2.1 Visualizing unary, binary and ternary operators