Java Programming Quiz

Sarah’s program takes two numbers and adds them only if both are positive. Which code snippet works?

• if (num1 > 0 && num2 > 0) int sum = num1 + num2;

• if (num1 > 0 || num2 > 0) int sum = num1 + num2;

• if (num1 = num2) int sum = num1 + num2;

• int sum = num1 + num2; if (sum > 0)

John’s calculator uses a Scanner named input to read two integers. Which line correctly declares and reads the first number?

• int num1 = input.nextInt();

• int num1 = Scanner.nextInt();

• Scanner num1 = input.nextInt();

• int num1 = input.nextLine();

Maria checks if a number is between 10 and 20 (inclusive). Which condition should she use?

• if (num >= 10 && num <= 20)

• if (num >= 10 || num <= 10)

• if (num >= 10 || num <= num2) int diff = num1 - num2;

• if (num1 == num2) int diff = num1 - num2;

Lisa’s program fails because she didn’t import Scanner and didn’t declare it properly. Which line fixes both?

• import java.util.Scanner; Scanner scan = new Scanner(System.in);

• Scanner scan = new Scanner(); import java.util.Scanner;

• import Scanner; Scanner scan = System.in;

• Scanner scan = new Scanner(System.in); import java;

Anna’s program compares two numbers and prints “Equal” if they match. Which code is correct?

• if (num1 == num2) System.out.println("Equal");

• if (num1 = num2) System.out.println("Equal");

• if (num1 != num2) System.out.println("Equal");

• if (num1 > num2) System.out.println("Equal");

Mike divides two numbers but only if the second isn’t zero. Which code prevents division by zero?

• if (num2 != 0) int result = num1 / num2;

• if (num2 == 0) int result = num1 / num2;

• int result = num1 / num2; if (num2 != 0)

• if (num1 != 0) int result = num1 / num2;

Emily’s calculator lets the user choose between adding or multiplying. Which code structure works?

• if (choice == 1) int result = num1 + num2; else if (choice == 2) int result = num1 * num2;

• if (choice = 1) int result = num1 + num2; else int result = num1 * num2;

• int result = num1 + num2; if (choice == 2) int result = num1 * num2;

• if (choice > 0) int result = num1 + num2 * num2;

David reads a number and a name in sequence. Which pair of Scanner methods should he use?

• nextInt() then.nextLine()

• nextLine() then.nextInt()

• nextInt() then.nextDouble()

• nextLine() then.close()

Rachel subtracts two numbers and checks if the difference is positive. Which code works?

• int diff = num1 - num2; if (diff > 0)

• int diff = num1 + num2; if (diff > 0)

• if (num1 - num2 > 0) int diff = num1 + num2;

• int diff = num1 - num2; if (diff > 10)

Ethan prints “Big” if a number is greater than 10, otherwise “Small”. Which code works?

• if (num > 10) System.out.println("Big"); else System.out.println("Small");
  

• if (num < 10) System.out.println("Small"); else System.out.println("Big");

• if (num = 10) System.out.println("Big"); else System.out.println("Small");

• System.out.println("Big"); if (num > 10) else System.out.println("Small");