Conditional Structures and Loops - A Concise and Practical Introduction to Programming Algorithms in Java - page 35

2.2.3 Nested conditionals

Conditional structures may also be nested yielding various complex program
workflows. For example, we may further enhance the output message of our
former date comparison as follows:

int h1 =... , m1 =... , s1 =...;
int h2 =... , m2 =... , s2 =...;
int hs1 = 3600

∗ ∗

h1 + 60 m1 + s 1 ;

int hs2 = 3600 ∗ h2 + 60 ∗ m2 + s 2 ;

int d=hs2 − hs1 ;

if (d > 0) { System . out . println ( "larger" ); }

else
{ if (d < 0)
{ System . out . println ( "smaller" ); }
else
{ System . out . println ( "identical" ); }

}

Since these branching statements are all single instruction blocks, we can also
choose to remove the braces as follows:

if (d>0) System.out.println("larger");
else
if (d<0)
System.out.println("smaller");
else
System.out.println("identical");

However, we do not recommend it as it is a main source of errors to novice
programmers. Note that in Java there is no shortcut 1 for else if . In Java, we
need to write plainly else if . There can be any arbitrary level of nested if
else conditional statements, as shown in the generic form below:
if (predicate1)
{ Block1 }
else
{ if (predicate2)
{ Block2 }
else
if (predicate3)
{

Block3 }

else
{ ...
}

}

1 In some languages such as Maple R

, there exists a dedicated keyword like elif .