Lec5: Variable/Integer, Assignment Operators, Scanner

Question 1

What will be displayed as a result of executing the following code?

int value1 = 9;
System.out.println(value1);
int value2 = 45;
System.out.println(value2);
System.out.println(value3);
value3 = 16;

Answer 1

Nothing, this is an error (did not declare the variable before printing it out).

Question 2

Programming style includes techniques for consistently putting spaces and indentation in a program so visual cues are created.

Answer 2

True

Question 3

What is the value of cube after the following code executes?

double cube, side;
side = 5.0;
cube = Math.pow(side, 3);

Answer 3

125.0

Question 4

Which statement(s) is/are equivalent to the following?

Answer 4

number = number + 1;
number++;

Question 5

What will be the values of x and y after running the following code?

int x = 25, y = 8;
x += y++;

Answer 5

x = 33, y = 9

Question 6

Which statement(s) is/are equivalent to the following?

number = number * 2;

Answer 6

number *= 2

Question 7

Which is the value of the number after the following statements are executed?

int number = 10;
number += 5;
number -= 2;
number *= 3;

Answer 7

39

Question 8

Which of the following function(s) will return the value of x, rounded to the nearest whole number?

Answer 8

Math.round(x)

Question 9

Which of the following represents the declaration and initialization of a variable named twoThirds, initialized to the floating-point constant two-thirds?

Answer 9

double twoThirds = 2/3.0;
double twoThirds = 2.0/3;
double twoThirds = (double)2/3;
double twoThirds = 2.0/3.0;
double twoThirds = 2/(double)3;

Question 10

If x and y are Java variables of type double, write the java code for the expression : x^2 + 2/3y -5

Answer 10

(Math.pow(x, 2) + 2) / (3 * y - 5)

Question 11

Which scanner class method would you use to read a string as input?

Answer 11

nextLine

Question 12

What is the appropriate import statement to use when you plan on using the scanner in your program?

Answer 12

import java.util.*;
import java.util.Scanner;

Question 13

Give the data type of the result of the operation: Math.round(2, 6)

Answer 13

Long

Question 14

Consider the following variable:

int totalSeconds = 50000;

After you computed the number of whole hours this gives, which of the following statements would figure out the total number of leftover minutes, and then store it in the variable named minutes?

Answer 14

int minutes = totalSeconds % 3600 . 60;

Question 15

Determine the output of the following code:

int bill = 11, emily = 3, omar;
omar = bill * –emily;
System.out.printf(“%3d%3d%3d\n”, bill, emily, omar);

Answer 15

11 2 22

Question 16

What is the value of the expression below?

Math.pow(Math.abs(3-6), Math.sqrt(4))

Answer 16

9

Question 17

Assume the variable declarations below for this problem:

int x = 3, y = 2, z = x + y;

Which of the following output statements correctly displays:

3 + 2 = 5

Answer 17

System.out.print(x + “+” + y “=” + z);

Question 18

What is the output from the following statements?

double x = 3.1415;
System.out.printf(“%8.3f\n”, x);

Answer 18

3.142

Question 19

Determine the output of the following code:

int kim = 6, kumail = 4, mick = 1;

mick += kim– + –kumail;
System.out.printf(“%3d%3d%3d\n”, kim, kumail, mick);

Answer 19

5 3 10

Question 20

Which of the following does not contain a syntax error?

Answer 20

num = a * (b + c);

Question 21

What will be the value of x after running the following code?

int x, y = 4, z = 6;
x = (y++) * (++z);

Answer 21

28

Question 22

Which of the following will NOT display the string “Welcome” followed by a newline character?

Answer 22

System.out.println(“%s\n”, “Welcome”);

System.out.printf(“%s”, “Welcome”);

System.out.printf(“s\n”, Welcome”);

System.out.print(“Welcome”);

Question 23

Which of the following statements will print out the character and NOT the integer for the following char declaration:

char fred = 102;

Answer 23

System.out.printf(%c\n”, fred);

Question 24

What will the following code print out?

int carlos = 81, maria = 20;

System.out.printf(“%d %d\n”, –carlos, maria++);

Answer 24

80 20

Question 25

What will be displayed after the following statements have been executed?

final double X = 61.1

X = 54.3;

System.out.println(“X = “ + X);

Answer 25

Nothing, this is an error. Permanently named constants should be declared and initialized in the same line.

Question 26

Determine the output of the following code:

int a = 9, b = 4, c = 23;
c %= b++;
a = c + b * 3 + a;
System.out.printf(“%3d%3d%3d\n”, a, b, c);

Answer 26

27 5 3