61. A program should continue receiving an input number and outputting that number squared until the input number is negative. Which control structure should be used?
Answer: B
A while loop should be used.
A while loop is the appropriate control structure for this program because it allows the program to continue executing as long as the input number is non-negative, thus repeatedly squaring the number until a negative value is received.
A) for loop
A for loop is not suitable for this scenario because it typically iterates a specific number of times or over a particular range. Since the number of iterations depends on user input, a for loop would not be able to handle an indefinite amount of input until a negative number is entered.
B) while loop
The while loop is the correct choice as it checks the condition before each iteration. In this case, it can keep receiving and processing input numbers until the condition of receiving a negative number is met, making it ideal for this type of input validation scenario.
C) if statement
An if statement does not provide a way to repeatedly execute a block of code based on a condition. It would only evaluate the condition once and execute the code block a single time, failing to accommodate the requirement of continuous input until a negative number is encountered.
D) Multiple if statements
While multiple if statements could evaluate conditions separately, they would not allow for continuous input and processing in a loop. They would execute only once for each condition checked, and therefore would not fulfill the need for the program to keep running until a negative number is entered.
Conclusion
In summary, the while loop is the most suitable control structure for this program as it allows for repeated execution based on a condition that is checked continuously. The other options fail to provide the necessary repetition or control flow needed to handle indefinite user input effectively.