CPS180 Final Exam

What is the return value of "SELECT".substring(0, 5)?

"SELEC"

Which of the Boolean expressions below has incorrect syntax?

(x != 0) || (x = 0)

What is y? int x = 0; int y = 0; switch (x+1){ case 0: y = 0; case 1: y = 1; default: y = -1; }

-1

What is the output from System.out.println((int)Math.random() * 4)?

0

public static void main(String[]args) { int[]x={0,1,2,3,4,5}; xMethod(x,5); } public static void xMethod(int[]x,int length) { for(int i=0; i<length; i++) System.out.print(" "+x[i]); }

0 1 2 3 4

double []myList = {1,5,5,5,5,1}; double max = myList[0]; int indexOfMax=0; for(int i=1; i<myList.length;i++) { if(myList[i]>max) { max=myList[i]; indexOfMax=i; } } System.out.println(indexOfMax);

1

int list[] = {1,2,3,4,5,6}; for(int i = 1; i<list.length; i++) list[i] = list[i-1]; for (int i = 0; i<list.length; i++) System.out.print(list[i] + " ");

1 1 1 1 1 1

public static void main(String[]args) { int[]myList = {1,2,3,4,5,6}; for(int i = myList.length-2;i>=0; i--) myList[i+1]=myList[i]; for(int e: myList) System.out.print(e + " "); }

1 1 2 3 4 5

for(int i = 0; i<15; i++){ if(i % 4 == 1) System.out.print(i + " ");

1 5 9 13

int[] x = {120, 200, 016}; for(int i = 0; i<x.length; i++) System.out.print(x[i] + " ");

120 200 14

int i = 1; int j = 1; while(i<5){ i++; j = j*2; } System.out.println(j);

16

Assume that the ASCII code for character c is 99 and for a is 97. What is the printout of the following code? System.out.println('a' + 'c');

196

int x = 3; int y = 4; switch(x+3){ case 6: y=0; case 7: y=1; default: y +=1; }

2

int[]list1 = {3,2,1}; int[]list2 = {1,2,3}; list2=list1; list1[0]=0; list1[1]=1; list2[2]=2; for(int i=list2.length-1; i>=0; i--) System.out.print(list2[i] + " ");

2 1 0

int[]myList = {1,2,3,4,5,6}; for(int i=1; i<myList.length; i++) myList[i-1]=myList[i]; for(int e: myList) System.out.print(e + " ");

2 3 4 5 6 6

If you declare an array double[] list = {3.4, 2.0, 3.5, 5.5}, list[1] is

2.0

What is x after evaluating the following? x = (2 > 3) ? 2 : 3;

3

double []myList = {1,5,5,5,5,1}; double max = myList[0]; int indexOfMax=0; for(int i=1; i<myList.length;i++) { if(myList[i]>=max) { max=myList[i]; indexOfMax=i; } } System.out.println(indexOfMax);

4

public static void main(String[] args) { int [][]values = {{3,4,5,1}, {33,6,1,2}}; for(int row = 0; row<values.length; row++) { System.out.print(m(values[row]) + " "); } } public static int m(int[]list) { int v = list[0]; for(int i = 1; i<list.length; i++) if(v<list[i]) v=list[i]; return v; }

5 33

int sum = 0; int item = 0; do{ item++; sum +=item; if(sum>4)break; }while (item<5); System.out.println(sum);

6

The expression (int)(76.0252175 * 100) / 100 evaluates to

76

int[][]matrix = new int[5][5]; for(int column = 0; column<matrix[4].length; column++); matrix[4][column] = 10;

A syntax error, because column is not defined.

Analyze the following code fragments that assign a boolean value to the variable even. //Code 1: if(number % 2 == 0) even= true; else even = false; //Code 2: even = (number % 2 == 0) ? true: false; //Code 3: even = number % 2 == 0;

All three are correct, but Code 2 is preferred. WRONG!

//Code 1: int number = 45; boolean even; if(number % 2 == 0) even = true; else even = false; //Code 2: boolean even = (number % 2 == 0);

Both Code 1 and Code 2 are correct, but Code 2 is better.

//Enter an integer Scanner input = new Scanner(System.in); int number = input.nextInt(); if(number <= 0) System.out.println(number);

If number is zero, number is displayed.

Which of the following is a constant, according to Java naming conventions?

MAX_VALUE

boolean even = false; if(even){ System.out.println("It is even!");

The code displays nothing.

int x = 1; while(0<x) && (x<100) System.out.println(x++);

The code does not compile because (0 < x) && (x < 100) is not enclosed in a pair of parentheses.

int sum = 0; for(int i = 0; i< 100000; i++){ Scanner input = new Scanner(System.in); sum += input.nextInt(); }

The program compiles and runs, but it is not efficient and unnecessary to execute the Scanner input = new Scanner(System.in); statement inside the loop. You should move the statement before the loop.

public class Exam1 { public static void main(String[]args) { int[] oldList = {1,2,3,4,5}; reverse(oldList); for(int i = 0; i<oldList.length; i++) System.out.print(oldList[i] + " "); } public static void reverse(int[]list) { int[]newList = new int[list.length]; for(int i = 0; i<list.length;i++) newList[i] = list[list.length - 1 - i]; list = newList; } }

The program displays 1 2 3 4 5.

int []a = new int[4]; a[1] = 1; a = new int[2]; System.out.println("a[1] is " + a[1]);

The program displays a[1] is 0.

public static void main(String[]args) { xMethod(new double[]{3,3}); xMethod(new double[5]); xMethod(new double[3]{1,2,3}); } public static void xMethod(double[]a) { System.out.println(a.length); }

The program has a compile error because xMethod(new double[3]{1, 2, 3}) is incorrect.

public static void main(String[]args) { int[]x=new int[5]; for(int i=0; i<x.length;i++) x[i]=i; System.out.println(x[i]); }

The program has a syntax error because i is not defined in the last statement in the main method.

int month = 09; System.out.println("month is " +month);

The program has a syntax error, because 09 is an incorrect literal value.

boolean[][]x=new boolean [3][]; x[0] = new boolean[1]; x[1] = new boolean [2]; x[2] = new boolean [3]; System.out.println("x[2][2] is " + x[2][2]);

The program runs and displays x[2][2] is false.

boolean even = false; if(even = true){ System.out.println("It is even!");

The program runs fine, but displays nothing. WRONG!

int x; double d = 1.5; switch(d){ case 1.0: x=1; case 1.5: x=2; case 2.0: x=3;

The switch control variable cannot be double.

What is the index variable for the element at the first row and first column in array a?

a[0][0]

What is the exact output of the following code? double area = 3.5; System.out.print("area"); System.out.print(area);

area3.5

boolean even = false; System.out.println((even ? "true" : "false"));

false

int number = 25; int i; boolean isPrime = true; for(i = 2; i< number; i++){ if(number %i == 0){ isPrime = false; break; } } System.out.println("i is " +i+ " isPrime is " +isPrime);

i is 5 isPrime is false

int number = 25; int i; boolean isPrime = true; for(i=2; i<number && isPrime; i++){ if(number%i ==0){ isPrime = false; } } System.out.print(i); System.out.print(isPrime);

i is 6 isPrime is false

for( ; ; ) System.out.println("Welcome to Java");

prints out Welcome to Java forever

What is the value of the following expression? true || true && false

true

What is the printout of the following code: double x = 10.1; int y = (int)x; System.out.println("x is " + x + " and y is " + y);

x is 10.1 and y is 10

int x = 1; int y = x+ x++; System.out.println("y is " +y);

y is 2

int x = 1; int y = x = x+1; System.out.println("y is " +y);

y is 2 because x + 1 is assigned to x and then x is assigned to y.

Do the following two programs produce the same result? Program I: public class Test { public static void main(String[ ] args) { int[ ] list = {1, 2, 3, 4, 5}; reverse(list); for (int i = 0; i < list.length; i++) System.out.print(list[i] + ʺ ʺ); } public static void reverse(int[ ] list) { int[ ] newList = new int[list.length]; for (int i = 0; i < list.length; i++) newList[i] = list[list.length - 1 - i]; list = newList; } } Program II: public class Test { public static void main(String[ ] args) { int[ ] oldList = {1, 2, 3, 4, 5}; reverse(oldList); for (int i = 0; i < oldList.length; i++) System.out.print(oldList[i] + ʺ ʺ); } public static void reverse(int[ ] list) { int[ ] newList = new int[list.length]; for (int i = 0; i < list.length; i++) newList[i] = list[list.length - 1 - i]; list = newList; } }

yes