Question

(Single Array Questions) Write single statements that perform the following one-dimensional array operations: a) Initialize the 10 elements of integer array counts to zero. b) Add 1 to each of the 15 elements of integer array bonus. c) Read 12 values for double array month 7 yTemperatures from the keyboard. d) Print the 5 values of integer array bestscores in column format.

Short answer

a) Use a for loop to set each element of 'counts' to 0. b) Use a for loop to increase each element of 'bonus' by 1. c) Use a Scanner and a for loop to read values into 'monthlyTemperatures'. d) Use a for loop to print each 'bestScores' element on a new line.

Step-by-step solution

Initializing Array Elements to Zero

To initialize all elements of an integer array named 'counts' with 10 elements to zero, you can use a for loop that iterates through each element setting it to zero: for (int i = 0; i < counts.length; i++) { counts[i] = 0;}

Adding 1 to Each Element of an Array

To add 1 to each of the 15 elements in an integer array called 'bonus', use a for loop to iterate over each element and increase its value by 1: for (int i = 0; i < bonus.length; i++) { bonus[i] += 1;}

Reading Array Values from the Keyboard

To read 12 values into a double array named 'monthlyTemperatures', use a Scanner object to input values from the user: Scanner input = new Scanner(System.in);for (int i = 0; i < monthlyTemperatures.length; i++) { monthlyTemperatures[i] = input.nextDouble();}

Printing Array Values in Column Format

To print each of the 5 values of an integer array called 'bestScores' in column format, use a for loop to iterate and print each element on a new line: for (int i = 0; i < bestScores.length; i++) { System.out.println(bestScores[i]);}

Key concepts

Initializing Arrays

In C++, initializing arrays is a fundamental operation that sets the initial state of an array before use. For instance, setting all elements of an array to zero is a common practice when the values will be accumulated or replaced later on.

Considering the example provided, an integer array named 'counts' with 10 elements can be initialized to zero using a for loop. The loop runs from the first index (0) to the last index (array length - 1), and sets each element to zero:

• for (int i = 0; i < 10; i++) {
  counts[i] = 0;
  }

It's important to note that uninitialized arrays contain garbage values, which are essentially random bits present in memory. Therefore, properly initializing an array ensures predictable and defined behavior of your program.

Iterating Over Arrays

To iterate over arrays in C++, you will commonly use for loops to access each element sequentially. This is particularly useful when performing operations like updating each element's value.

In the exercise, we needed to add 1 to each of the 15 elements of an integer array 'bonus'. A for loop made this task straightforward:

• for (int i = 0; i < 15; i++) {
  bonus[i] += 1;
  }

Using array indices, the loop iterates through the 'bonus' array from start to end, incrementing each value. Iteration plays a crucial role in array manipulations and being comfortable with it allows you to perform various operations across array elements efficiently.

Reading User Input into Arrays

Accepting user input into arrays requires capturing data entered by the user and storing it into the correct array positions. The process usually occurs in a loop that runs for the number of elements you wish to input.

To read user inputs for the 'monthlyTemperatures' array with 12 elements, you can use the following:

• Scanner input = new Scanner(System.in);
  for (int i = 0; i < 12; i++) {
  monthlyTemperatures[i] = input.nextDouble();
  }

Each iteration prompts the user for a value and stores it in the corresponding index. It is essential to ensure that the user inputs the correct type of data (in this case, a double) to prevent runtime errors or incorrect data storage.

Printing Array Elements

The printing of array elements is a common way to display the contents of an array to the user. Whether in a single line or formatted differently, the output helps in understanding the current state of array data.

For the 'bestScores' array, presenting its values in a column can be done like this:

• for (int i = 0; i < 5; i++) {
  System.out.println(bestScores[i]);
  }

This loop traverses the 'bestScores' array and prints each element on a new line, resulting in a columnar display. Printing arrays can be customized in numerous ways depending on the desired output, for example, formatting numbers or aligning columns for better readability.