Question

Which common error is present in the code below, which is intended to calculate the average value from a sum of numbers?

double total;int n;double input;while (cin >> input) total

A) The variable 'total' is not initialized.
B) The loop does not iterate over all the input values.
C) There is a type mismatch in the 'input' variable.
D) There is no termination condition for the loop.

Answer 1

D) There is no termination condition for the loop

Step-by-step explanation:

The code lacks a proper loop structure, and the statement after the while condition seems incomplete. A typical loop structure includes a set of braces {} to define the scope of the loop. If the intention is to sum up input values until the end of input is reached, the code should be something like this lol:

#include <iostream>

int main() {

double total = 0;

double input;

int n = 0;

while (std::cin >> input) {

total += input;

n++;

}

if (n != 0) {

double average = total / n;

std::cout << "Average: " << average << std::endl;

} else {

std::cout << "No input provided." << std::endl;

}

return 0;

}

This example assumes that the intention is to calculate the average value from a sum of numbers until the end of input is reached.

Answer 2

The error in the code is that the variable 'total' is not initialized, which can lead to undefined behavior or incorrect results in the program.

Step-by-step explanation:

The common error present in the code snippet given is option A: The variable 'total' is not initialized. In programming, especially when dealing with accumulators such as a sum, it is crucial to initialize variables properly to ensure they start with a correct default value, often zero for a sum. Since 'total' is meant to accumulate the sum of inputs to later calculate an average, not initializing it can result in undefined behavior or incorrect results as it may start with any garbage value present at that memory location.

The loop is intended to read numbers indefinitely until an error or end-of-file condition occurs on the input stream, so there is no explicit termination condition for the loop, making option D incorrect. While options B and C are valid types of errors in some contexts, they are not applicable here: the loop will iterate over all input values correctly given the use of cin, and there is no type mismatch in the 'input' variable since both 'input' and 'total' are of type 'double'.