Question

What is the output of the following program segment? int temp [5] \\[ \begin{array}{l} \text { For }(\mathrm{int} \mathrm{i}=0 ; \mathrm{i} < 5 ; \mathrm{i}++) \\ \text { temp }[\mathrm{i}]=2 * \mathrm{i}-3 \mathrm{r} \\ \text { for }(\mathrm{int} \mathrm{i}=0 ; \mathrm{i} < 5 ; \mathrm{i}++) \\ \text { cout } << \text { temp }[\mathrm{i}] << \mathrm{m}, \end{array} \\] cout \( < < \) endl cout \( < < \) endl;

Short answer

The program outputs: "-3m -1m 1m 3m 5m" followed by two newline characters.

Step-by-step solution

Understand the code structure

The code consists of two loops. The first loop initializes and updates an array `temp` of length 5. The second loop prints each element of the array followed by the character `m`. Finally, the output is followed by two newline characters using `cout << endl` twice.

Analyze the first loop

The first loop iterates with `i` ranging from 0 to 4. For each iteration, it calculates `temp[i]` using the formula `2 * i - 3`. Thus, the assignments are: - When `i = 0`: `temp[0] = 2 * 0 - 3 = -3` - When `i = 1`: `temp[1] = 2 * 1 - 3 = -1` - When `i = 2`: `temp[2] = 2 * 2 - 3 = 1` - When `i = 3`: `temp[3] = 2 * 3 - 3 = 3` - When `i = 4`: `temp[4] = 2 * 4 - 3 = 5`

Analyze the second loop

The second loop again iterates with `i` from 0 to 4. In each iteration, it outputs the current element of `temp` and then the character `m` without newline: - Output `-3m -1m 1m 3m 5m`

Add the newlines

After the second loop, the program outputs `endl` twice, which means it adds two newline characters. This means after the sequence `-3m -1m 1m 3m 5m`, there would be two lines skipped in the output.

Key concepts

loops in C++

Loops in C++ are a fundamental concept that enable programmers to perform repetitive tasks efficiently. They are indispensable when you need to execute the same block of code multiple times. In this exercise, two types of loops are used, specifically `for` loops.
A `for` loop in C++ consists of three main parts:

• Initialization: This is where you set the initial counter variable. In the exercise, `int i = 0` initializes the counter to zero.
• Condition: This controls how long the loop runs. It checks if the condition is true before each iteration. Here, the loop continues as long as `i < 5`.
• Increment: The counter variable is updated at the end of each loop iteration. In this case, `i++` increments `i` by one.

By using these loops, the program systematically processes each element of an array. The first loop assigns values to each element based on a formula, while the second loop is used to output these values. Loops help in reducing code redundancy and managing repetitive tasks efficiently.

arrays in C++

Arrays in C++ are used to store a collection of data. They are particularly useful when you have a list of items of the same data type, such as integers, which you need to process together. An array stores multiple values in a single variable, which can be accessed using an index.
In this exercise, an integer array `temp` of size 5 is used. This means it can hold 5 integer values:

• The array indices start at 0 and run to one less than the array size, which is 4 for our 5-element array.
• Values are assigned to each part of the array through `temp[i]` where `i` is the loop counter.

The values assigned in the example are computed using the expression `2 * i - 3`, effectively storing a computed sequence of numbers in the array. Once the elements are initialized, you can access and manipulate them with the same loop construct, utilizing the power of both arrays and loops to handle groups of data efficiently.

output formatting in C++

Output formatting in C++ is crucial for presenting data in an organized and readable way. By using `cout`, you can display text and variables to the console. Formatting improves clarity, especially when outputting multiple data points, like in arrays.
In the code from the exercise, output formatting is applied in a couple of ways:

• The characters and variables are printed in sequence within the loop using `cout`. Each element of the array `temp` is displayed, followed by the character 'm'.
• Additionally, `cout << endl` is used to control the alignment of text by inserting newline characters. This is crucial as it separates lines and clarifies the output visually by providing space.

By understanding these simple output formatting techniques, you can enhance the readability and professionalism of your program's output, ultimately aiding users in interpreting the results of their code executions.