Question

Assume that the file data.txt exists and contains several lines of text. Write a short program using the while loop that displays each line in the file.

Short answer

Based on the provided step-by-step solution, answer the following question: **Question:** Write a short program using a while loop that reads and displays each line from the file "data.txt". **Answer:** Here is a short program that reads and displays each line from the file "data.txt" using a while loop: ```python file = open("data.txt", "r") line = file.readline() while line: print(line, end="") line = file.readline() file.close() ```

Step-by-step solution

Open the file

First, open the file "data.txt" using the built-in `open` function, which takes two arguments: the file's name and mode. In this case, the mode will be 'r' (read mode). Assign the file object to a variable, for example `file`. ```python file = open("data.txt", "r") ```

Read each line using a while loop

Now, read each line in the file using the while loop. Initialize a variable `line` by reading the first line using the `readline` function. Inside the while loop, check if the `line` is not empty, which means there are more lines to read. ```python line = file.readline() while line: ```

Display each line

Inside the while loop, print the line and then read the next line using the `readline` function. This will ensure that each line is displayed until the end of the file. Make sure that the `print` function has the parameter `end=""` to avoid extra line breaks. ```python print(line, end="") line = file.readline() ```

Close the file

After reading all the lines and exiting the while loop, it is necessary to close the file using the `close` function. ```python file.close() ``` Now, putting all the steps together, the final program looks like this: ```python file = open("data.txt", "r") line = file.readline() while line: print(line, end="") line = file.readline() file.close() ```