Exam & Solution - A Concise and Practical Introduction to Programming Algorithms in Java - page 227

11
Exam & Solution

The 2-hour exam below gives an overall review of the main concepts of
programming in Java. The four independent exercises are given with their
corresponding solutions.

Solution 11.1 (Mysterious recursive function)

- Consider the following program which compiles without any error:

public class MysteriousProgram {
public static void display( int [] tab) {
for ( int i=0; i < tab . length ; i++)
System . out . print ( tab [ i ] + "" );
System . out . println () ;
} public static void swap2( int a, int b)

{

int tmp = a ;
a=b;
b=tmp;
} public static void swap3( int [] tab, int i, int j)

{

int tmp = tab [ i ] ;
tab [ i ] = tab [ j ] ;
tab [ j ] = tmp;

}

public static void mysterious( int [] tab, int k) {

for ( int j=k; j < t a b . l e n g t h ; j ++) {

swap3( tab , k , j ) ;

display(tab) ;
swap3( tab , k , j ) ;

}

}