Chapter 7, Problem 1RE

a.

Explanation of Solution

Allocating an array

• In java, an array is created with the keyword new that is used for allocating memory.
• Hence allocating an array consists of two steps that is to declare a variable of the desired array type and to allocate the memory that will hold the array using new keyword and assigning it to the array variable.
• In java, all arrays are dynamically allocated.
• The code for allocating an array of ten integers is

  // Declaring an array

  int[] nums = new int[10];

b.

Explanation of Solution

Declaring initial element of the array

• In java, an array is created with the keyword new that is used for allocating memory.
• In java, all arrays are dynamically allocated.
• An integer variable can be used as the index of the array.
• Hence here 0 is the index of the array.
• The code for putting 17 as the initial element of the array is

  // Declaring initial element

  nums[0] = 17;

c.

Explanation of Solution

Declaring last element of array

• In java, an array is created with the keyword new that is used for allocating memory.
• In java, all arrays are dynamically allocated.
• An integer variable can be used as the index of the array.
• Hence here 9 is the last element of the array.
• The code for putting 29 as the last element of the array is

  // Declaring last element

  nums[9] = 29;

d.

Explanation of Solution

Filling remaining elements with -1

• In java, an array is created with the keyword new that is used for allocating memory.
• In java, all arrays are dynamically allocated.
• The for loop is executed for filling the remaining elements with -1.
• The code for filling the remaining elements with -1 is

  // Execute for loop

  for (int i = 1; i < 9; i++)

  {

  nums[i] = -1;

  }

e.

Explanation of Solution

Adding 1 to each element of array

• In java, an array is created with the keyword new that is used for allocating memory.
• In java, all arrays are dynamically allocated.
• The for loop is executed for adding 1 to each element of array.
• The code for adding 1 to each element of array is

  // Execute for loop

  for (int i = 0; i < nums.length; i++)

  {

  nums[i]++;

  }

f.

Explanation of Solution

Printing all elements of array one per line

• In java, an array is created with the keyword new that is used for allocating memory.
• In java, all arrays are dynamically allocated.
• The for loop is executed for printing all elements of array one per line.
• The code for printing all elements of array one per line is

  // Execute for loop

  for (int num : nums)

  {

  System.out.println(num);

  }

g.

Explanation of Solution

Printing all elements of array in a single line

• In java, an array is created with the keyword new that is used for allocating memory.
• In java, all arrays are dynamically allocated.
• Here if condition is executed inside the for loop for printing all elements of array in a single line.
• The code for printing all elements of array in a single line is

  // Execute for loop

  for (int i = 0; i < nums.length; i++)

  {

    // Execute if condition

  if (i < nums.length - 1)

  // Print the statement

  System.out.print(nums[i] + ",");

  else

  // Print the statement

  System.out.println(nums[i]);

  }