Practice Test

1. What is wrong with the following code:

class Wrong {

     public static void main(String args[]) {

int x = 3;

printX();

     }

     public static void printX() {

System.out.println(“x is ”  + x);

     }

}

2.)  Fix the above using parameters

3.)  Why can’t you write a swap method in Java?

4.) Write a for loop that iterates 100 times.

5.) How would you, in Java, get a random number between 1 and 100?

6.)  Write a method called coinToss that returns 0 for heads and 1 for tails.

7.) For each of the following, provide the recursive definition and the base case:

            a.) Sum

            b.) Factorial

            c.)  Power

8.) Pick one of the above and write a recursive method in Java to calculate it.

9.) What is an Object in Object Oriented Programming?  

10.) What does it mean for a program to be event-driven?

11.) Given the following method that you do not need to implement, but can use:

int min(int a[], int start);

that returns the position of smallest element in a[], starting at position a[start], write the code for Selection Sort.

void selectionSort(int[] data) {

}