Question

include \(<\) iostream \(>\) using namespace std; int main ( ) \(\\{\) int num, bigNum, power, count; cout \(<<\) "… # A) // This program uses a loop to raise a number to a power. # include \(<\) iostream \(>\) using namespace std; int main ( ) \(\\{\) int num, bigNum, power, count; cout \(<<\) "Enter an integer: "; \(\operatorname{cin} \quad>>\) num cout \(<<\) "What power do you want it raised to? "; cin \(>>\) power bigNum \(=\) num; while (count++ \(<\) power); bigNum \(*=\) num; cout \(<<\) "The result is \(<<\) bigNum \(<<\) endl return 0 \\} B) // This program averages a set of numbers. # include using namespace std; int main() \\{ int numcount, total; double average; cout \(<<\) "How many numbers do you want to average? "; cin \(>>\) numcount for \((\text { int count }=0 ; \text { count }<\text { numcount } ; \text { count }++)\) \\{ int num; cout \(<<\) "Enter a number: "; \\[ \operatorname{cin} \quad>>\text { num } \\] total \(+=n u m\) count \(++\) \\} average \(=\) total / numCount; cout \(<<\) "The average is \(<<\) average \(<<\) endl return 0 \\}

Short answer

Answer: To raise a number to a given power using a while loop, we can initialize a 'count' variable, and use it as the condition for the loop. In each iteration, multiply the result by the base number and increment the 'count' until it reaches the desired power. To calculate the average of a set of user-entered numbers using a for loop, we can ask the user for the number of values to be averaged and iterate based on that value. In each iteration, receive input for the next value, update the total sum, and finally divide the total by the number of input values to get the average.

Step-by-step solution

1. Headers and namespace

Include the iostream header to access standard input and output functions. Define the "std" namespace to simplify notation in the code.

2. Main function

Define the main function, which is the entry point of the C++ program.

3. Declare variables

Declare four integer variables: `num`, `bigNum`, `power`, and `count`. These variables will store the number, the result, the power to raise to, and the loop counter, respectively.

4. Receive input

Ask the user for an integer and store it in the `num` variable. Then, ask the user to enter the desired power and store it in the `power` variable.

5. Initialize bigNum

Set the value of `bigNum` equal to `num`, as it needs to start from the base number.

6. While loop

Use a while loop to raise `num` to the power `power`. Increment the `count` variable in the loop condition, and multiply `bigNum` by `num` in the loop body.

7. Display the result

Print the result, `bigNum`, to the console.

8. Return statement

Return 0 to signal the successful execution of the program. ### Program B ###

1. Headers and namespace

Include the iostream header to access standard input and output functions. Define the "std" namespace to simplify notation in the code.

2. Main function

Define the main function, which is the entry point of the C++ program.

3. Declare variables

Declare three variables: an integer `numCount`, a double `average`, and an integer `total`. These variables will store the number of input values, the average, and the sum, respectively.

4. Receive input

Ask the user for the number of values to be averaged and store it in the `numCount` variable.

5. For loop

Use the for loop to iterate based on the number of input values (`numCount`). Declare an integer variable `num` inside the loop to store the input values.

6. Receive input for each value

Ask the user for the next input value and store it in the `num` variable.

7. Update the total

Update the total by adding the current input value (`num`) to it in each iteration of the loop.

8. Calculate the average

Divide the total by the number of input values (`numCount`) and store the result in the `average` variable.

9. Display the result

Print the result, `average`, to the console.

10. Return statement

Return 0 to signal the successful execution of the program.

Key concepts

Variables in C++

Variables are fundamental to any program, including those written in C++. They act as storage containers in memory, holding data that can change as the program runs. In the provided exercises, we see the use of variables such as `num`, `bigNum`, `power`, `count`, `numCount`, `total`, and `average`. Each serves a different purpose within the respective program.
`num` and `bigNum` are integers declared to hold the base number and the result respectively, while `power` indicates how much `num` should be raised by. The `count` variable acts as a loop counter to track how many times the loop runs for raising the power.
In the averaging exercise, `numCount` holds the number of values that the user will input, while `total` accumulates their sum. Finally, `average` is a double, allowing it to store decimal points when calculating the average value of the input numbers. Declaring variables with the correct type ensures the program works as expected and prevents errors.

Input and Output in C++

In C++, input and output are typically handled through the standard library `iostream`. The keywords `cin` (console input) and `cout` (console output) are pivotal here. They allow the program to communicate with the user through the console or command line.
In the exercises, the program requests input from the user using `cin`. For the power exercise, it asks for an integer and a power to raise it by. For the average calculation, it prompts the user to specify how many numbers they will provide. Each input request is followed by storing the received data into appropriate variables, ensuring it can be used later in the program.
Conversely, `cout` is used to provide outputs such as prompts for input or the results of computations. It sends a message to the console to inform the user, such as "The result is" followed by the computed power of a number, or "The average is" followed by the calculated average. Proper use of input and output makes a program more interactive and user-friendly.

Loop Structures in C++

Loop structures are vital for executing a block of code multiple times in a program. C++ supports several loops, including `for` loops and `while` loops, as seen in the exercises.
The first exercise implements a `while` loop to repeatedly multiply a number by itself to achieve a power operation. The loop continues as long as a condition is met (e.g., `count < power`), incrementing a `count` variable with each iteration and accumulating a result in `bigNum`. This loop enables the program to perform repetitive tasks without manual intervention.
Alternatively, for the averaging program, a `for` loop is used. It's especially useful for a known number of iterations – precisely what is needed when the user specifies how many numbers they will enter. Declaring a loop variable such as `count`, the loop runs `numCount` times, prompting for input each time and updating the total accordingly. The `for` loop simplifies the code by condensing the loop control logic into one concise statement.
Understanding these loops helps programmers create efficient and readable code, allowing for automated repetition where needed.