Functions and Recursive Functions - A Concise and Practical Introduction to Programming Algorithms in Java - page 61

while (n > 0)

{

result ∗ =n ; // similar to result=result*n;

;
} return result ; /
}

n −−

}

class ExampleFactorial {

public static void main( String [ ] args )
System . out . println ( "6!=" +Toolbox . factorial (6) ) ;
}

}

Compiling and executing this program yields 6!=720 .

3.2.4 Functions with conditional statements

The former distance function of 3.2.2 takes two arguments x and y of type

double and returns the absolute value of their difference in a result of type
double . Let us recall the previous code...
static double distance(double x, double y)
{double result;
if (x>y) result=x-y;
else result=y-x;
return result;
}

§

This could have been rewritten more compactly as follows:

static double distance(double x, double y)
{if (x>y) return x-y;
else return y-x;}

In case functions or procedures use branching conditionals (such as if else
or switch case statements), we always have to make sure that whatever the
instruction workflow, the function will always reach an appropriate return
statement. The compiler checks all these different execution paths and may
complain with a missing return statement message error if this property is
not met. For example, try to replace the distance function by this erroneous
code:

static double distance(double x, double y)
{double result;
if (x>y) result=x-y; // forgot voluntarily the return statement
else return y-x;}